Slow Deity Science

Hello Civettes and Civfiends. I have been playing exclusively Deity and finding issues with early warmongering. I take out a Civ completely but the price usually costs me my Science edge.

I will take out an enemy Capitol pre-Turn 50. Though usually after having met 3 or 4 civs. I play Pangea only because I'm not fond of boats. Since I've removed that Capitol the cost of Army Maintenance makes things go slow. I usually am Tallish with 4 cities and I'm stuck with at best 300 Science close to around 1500AD... I am having issues putting up Oxford before turn 100 cause war is expensive and I may be in 1 or 2 defensive wars. So my population is lower cause my buildings are taking longer due to army investment but I want to move my focus away from peaceful play only. I prefer Domination Victories... What is the best way to get my Science/Population up with a large Army? I have heard many say the maintenance of an Army you don't use is just a waste of gold.

My usual position without Fighting in a War is 4-5 Cities Tall..400-600 Science by around 1500 AD ... Once the AI perceives you a threat(after you own a Capitol or go after 2) It really starts getting sensitive and a pain in the rear...

the game is designed this way, as a warmonger you don't get friendships (trade/RAs) as easily.
If you go early war your main option would be to stay at war and defeat the AIs as quick as possible. Depending on the map type that would be with frigates or crossbows.

if you want to go for a science victory an early war is indeed not an optimal solution.

what's the turn time for 1500 AD on standard? If you like domination just keep going to the bottom half of the tech tree and wipe everyone else. But even as a warmonger I prefer to have CBs or XBs to fight, not nearly as early as you.

as for the science, just make sure you build the science buildings as soon as they're available in all cities. also use internal trade routes to grow, they probably won't be as useful when you send to other civs if they're easily plundered in wars

Early war is penalized so severely that the only civs that can really get away with it are the huns, the mongols, and arabia. The latter two because chariot archers are so powerful when they upgrade to something even better when you're just taken the first few cities of your campaign, and the huns because they get such effective early units.

Add Assyria. Their UA helps to partially mitigate the tech deficit, while the UU is a better meatshield than warriors and spears, and is a huge boon when attacking cities.