i cant connect to my friend's game, either by invite or direct connect, the wrong versin error pops up but we checked and we oth have the exact same version of both the game and GOG

what's going on?

Pak Mods have to be matching versions as well, and the same mods for both of you.

Also check out the Settings files
Documents\Larian Studios\Divinity Original Sin 2\PlayerProfiles\Uhuru NUru\modsettings.lsx
Documents\Larian Studios\Divinity Original Sin 2\PlayerProfiles\Uhuru NUru\config.lsx

The 4th line should match for both of you. Mines an older game version, but whatever it says, it should be the same for both.
<version major="3" minor="1" revision="3" build="5" />

Other than that, you can always try a fresh install, for both of you, with latest release.