Switching to republic took place five turns ago and while it was almost too early for that, it seems to be paying off. It's possible that doing something else first might have been a better choice but at least now it's impossible to bribe the East German workers. The key to switching to republic or democracy is having a decent economy. So, how to do that?
Build enough cities. If you have less space build the cities close enough to each other. Citymindist 4 means that you need to have 3 tiles between the cities. Having more is nice but overlapping is usually a good idea. If your cities have 6 tiles between them you most likely have the cities too far from each other. On this screenshot you may see some unclaimed space between the poor & old East Germany and the other nation next to us. This is because the border situation evolves and sometimes cities appear and disappear.
The second thing you may want to do is to improve the land. Building
roads is not just for moving your units between the cities. When you
build a road on a grassland, plans or desert you get trade for that
tile. With republic or democracy you get an additional trade resource
and that's huge. This means you get more gold and science. Don't use
such tiles if there are no roads, unless you really need to. For making
the land improvements you need at least one worker for each city you
have. Preferably more. If you have 1.5 workers / city that's usually
enough. Having too few workers is incredibly expensive since you will be
using unimproved tiles. From that pic you can see how East Germany
doesn't have all the tiles improved and this is bad.
Another thing is gold. It may be a good idea to have some gold for a rainy day but if you have too much like more than hundred with these stats it's usually too much. Use gold for purchasing city improvements. You get some value from city improvements and that adds to your economy. Compound interests is the effect you want to have and that you get by purchasing city improvements like markets, court houses etc.
You can get the same thing and the same economy by having less cities.
Building more and smaller cities takes time and getting the city
improvements is expensive. In the end it's good to have more land but
for a long time it's not that hard to catch up or do better with way
less cities. This means improving the land and avoiding expensive wars.
For avoiding those expensive wars you can always ally with someone and dissolve the alliance before the game is over. Agree about some kind of cancellation period like East Germany did when it recently allied with Finland. Yes, we are now allied in-game.
