Ok, I did have a look

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You are in Republic, that's fine. But, everything else I guessed is true. And, half of your cities are building Wealth...under Mobilization, to make things worse.
Seriously, your cities in general are ok; no blatant nonsense like Colossei. Spacing is somewhat accetable; you wasting quite some tiles, but I've seen worse. If you you wouldn't have about half your cities one tile away from the coast.
Technologically, you can trade for Electricity from China. But, you don't know if you have Rubber - Replacable Parts isn't known yet.
Nationalism is a questionable tech, better reseach to RP.
But in short: Your 'builder' style is not the real problem.
Warfare is...one single Cannon. Uncovered attackers. You will loose at least 2 cities in the interturn - because frontline cities are defended by one Spear, Coassck and MDI respectively (while a completely safe city like Murmansk has 4 units). Of course, since there is no strategic rail net, you cannot bring in reinforcements.
You have cash, und still not upgraded the Muskets.
And the worst: Moscow requires 4 Clowns, since you don't use the Luxury slider...
Now, is there any hope? You will loose a couple more cities, no way around that. But, those aren't important. It would be no problem to retake everything with Artillery, Cossacks and Rifles/Inf. In fact, any experienced player could win this without much work (since you managed to keep your reputation clean, a good move). Doubt you could, though. Sorry.
ToE isn't under construction so far, so even a tech lead should be easy to gain back.
But, you really need to improve your tactics. It's completely pointless to advance with Cossacks without cover (defenders/Cannons). Logistics; i.e. military railnet comes first. Unit construction.
I can only advise you to read some succession games, especailly 'Always War' games, and familiarize with warfare.
This is just a game where one can give no sound advice - except using the luxury slider, and stop building wealth there are no blatant, easy to correct mistakes. The inefficient warfare kills you; and this isn't something you could learn from a couple of advices here - but, you could just sit down and
think twice before moving a unit

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