[2023] cannot connect, "could not fully initialize epic online services"

Originally posted by Tahnval: TFP chose to force every player to use Epic online services. They also chose to not mention that fact on the Steam page for the game, which is deceptive.

You could probably get a refund through Steam's processes:

https://store.steampowered.com/steam_refunds

OP can try if they want, But, I think a refund is unlikely- At least not for that reason. It's literally a handshake for cross platform multiplayer; Which is advertised on the store- What method they use to achieve that is a matter of fruit choice, an apple, an orange, etc.

EoS supports cross platform to actual consoles- Not just between PC OSes. So for that reason along with several others, they moved to EoS for cross platform support since in the future the game is intended to be compatible between PC/PS5 or whatever new gen console might be available/XBONE or whatever new console might be availble.

To the OP, there are several solutions you could search up on the forum- If you're just playing SP the easiest one is probably to edit the platform.cfg file and remove 'EOS'; But if you're looking to play multiplayer, then I can't personally offer any solutions- Doesn't mean there isn't one, just that I don't know of one.