I tried playing MP with a friend via modppack from Aluysia without any additional mods (full VP+eui install) and it didnt work out. (constant desync which leads to crash) I thought it's because of VP. Tell me please how do you play multiplayer, if you have successful experience
The one I'm doing right now is with a group of people using playyourdamnturn.com. It lets you play a single turn and then pass it on to the next player. 77 turns in and we've run into no problems (aside from when we first started). But I can't guarantee that won't happen later on. It also takes much longer than an average Civ multiplayer game but you could probably do it fairly quickly if you share timezones with all other players. While it is far slower, this method also lets you think out your strategy far more, and since it doesn't rely on maintaining a stable internet connection, there's no risk of desync, so it has some advantages. If you do run into problems you can contact the help on that website and they might be able to fix them-like setting the game back a turn if things get glitchy.
As for standard multiplayer I currently don't have much advice on that. I've tried that too and had the same results as you several times. Even with pitboss, we had to go on 1 person at a time to ensure there would be no desync. It's a bit faster than playyourdamnturn though because you can do 1 turn to end a round, and then 1 turn to start the next one (then when the other player goes they'll end the round, and then play their turn in the next round). But eventually the server crashed so... not really recommended.
Ultimately I recommend playyourdamnturn. If your friend doesn't have the patience for it (like some of mine, unfortunately), then you can try reading some of the advice on the forum for things you can do to mitigate desyncs (although ultimately they were still too frequent for me to find acceptable). Or do Civ6 multiplayer, which far as I can tell is much more stable than Civ5 multiplayer, even with some mods.
