I have to second what
@pokiehl says here, this game was ripe with mistakes and you got punished for it, and other beating deity has nothing to do with them cheating or cooking games.
His criticism of your video is valid (especially the part about scouting far away with military units, you cant do that and then complain that you get invaded), and thus I'm not gonna repeat what he said, but add instead:
I havent watched the entire video, but right from turn 1 you made a pretty significant mistake, and that was your settle location.
Your starting location is
very good, but you chose the absolutely worst spot to settle out of any option that you had.
The reason your start location is good is that not only does it contain numerous 2f/2p tiles that you can keep working as you expand your borders, but that you had immediate access two such tiles (stone and forested hill), as well as a 3f/1p tile (bananas).
What truly makes this start really good though is that you lucked into a 2f/2p/1
faith tile.
This is extremely good on deity, because you are getting 1 faith for "free" (it is already on a good tile with solid base food/production, which is the most important yields in the start), which would have catapulted you towards getting the early and best pantheon picks.
So what I would have done in your case is to settle either two tiles to the left (costing you 1 turn), thereby giving you plenty of high yield tiles to work, or (my personal favourite) spend 3 turns and settle on the forest river right next to the 2f/2p/1f luxury tile to start working it immediately.
You picked the worst location however, in that you settled in an area that had nothing for you to really work, except 1f/2p and 2f/1p tiles.
Yes you get a little closer to the diamonds, but what good are those for you from the turn you settle?
It will take quite a while before you can work them, requires a builder, and gives an eureka that you often can get elsewhere.
Having an extra food or production from turn 1 is massive, and this is the sort of choice that really matters, because of how it lets you snowball from the second you settle.
Yes you might have to spend 1 turn to move your settler (costing you like 4 production), but you recoup that 4p loss (or 4f loss) in 4 turns (at which point you start going net positive) by moving that settler, which is pretty much a nobrainer for a 1 turn cost.
Later on you slot in god king, which is generally a bad card compared to urban planning (1 production in all cities, which is ridiculously good for a good part of the early game), and the only real reason you ever run god king is because it gives you faith.
But you would not have had to run that card if you had settled near the faith tile (which is what I would have done personally), letting you get even more production from urban planning as well.
After that its about using your production well.
I like your choice of going for a settler as your third production item (get two more cities as soon as you can to reduce the lead the AI has), but the second slinger was a bad choice.
Slingers (only one) are only decent for scouting a bit around your capital, fishing for an archery eureka (barbs usually), and then to use a pre-built archer for when you intend to invade someone (after you tech archery, you rush your target if its a viable target).
Warriors are what actually keep you alive.
Speaking of viable targets.
The second big mistake you did (after your choice of settle spot), was to not have leader yields active in your UI.
That one would have told you whether or not Cleopatra had a big army, which is very important intel to have in the early game because it tells you how you need to prioritize units.
There are two ways to stop her/delay her from attacking you.
The first one is to try to make friends with her (meet her with a scout, send delegation, trade some etc., then try to declare friendship), or to rely on deterrence.
Deterrence is usually by far the safest way to do so (though you can do both if Cleo is willing to friendship you), and you do so by raising your army value.
As I posted some days ago, the AI generally looks at your army value before it commits to an attack, and you can look at its army value too.
A value of 100 here shows that the AI has 5 warriors worth of combined units (the deity AI starting units), whereas you have 20 (your one warrior).
That is generally insufficient to prevent the AI from invading (the AI tends to look at you as a target if you have about 1/3rd of its military value, sometimes more, sometimes less), which is why you want to get a warrior to be really safe.
The second slinger does nothing for you at this point, since it gets utterly dumpstered by AI warriors if they do attack, and it has such a low army value score that it doesnt meaningfully impact the army value score, preventing an invasion in the first place.
Since you did not have that army value shown in your UI I can only speculate, but I suspect that it was probably closer to 150 or more, which happens a lot (and quickly) on deity if the AI starts investing in warriors.
To add to @pokiehls criticism on your scouting with military units:
You can scout, but only in a small circle around your capital (with a warrior), as you need it for defence.
The slinger can go and look a bit further for barbarians if you desire, but do not wander far off as you did here, as you might need to defend your city, or need help from the warrior in case a barb camp spawns near your capital.
But, and this regards scouting, the second you saw Cleopatras city location, you need to scout that area.
I am not telling you to run far away from the AI here, but keep your warrior or slinger relatively in between your capital and hers.
That way you will get several turns of notice in case she does send a big army (like her 5 warrior push in this video, which is 100% an invasion attempt even if she hasnt declared yet), which would have allowed you to start producing warriors of your own, as well as having your scouting warrior/slinger (that scouts her army) be located in such a way that it can retreat to your capital.
If she does then continue the attack (which is less likely had you made a second warrior instead of a second slinger), then you would have had 2 warriors to defend, as well as enough turns of head notice to start producing a third warrior.
With 3 warriors (one in the city to raise the city combat strength to 23, and two that are fortifying in tactically strong positions outside), the AI will generally lose its army on the attack because it keeps taking bad trades by attacking while you outheal it with your stacked defencive combat modifiers.
I'll be blunt about this:
The way you played this game has you deserving to lose, because you cannot continue playing so casually like its emperor, when you are playing on deity.
Small changes such as what we advocated here, is the difference between managing to comfortably win on deity, and getting mopped by the AI.
Some people dont like micromanaging the game to such an extent (which is totally fair), but it is necessary.
This has in other words
nothing to do with "other players cheating", but with you making some pretty big mistakes that will either get you killed or punished later on.
