I know the terrible feeling that you can't show your full skills in the game to players.
Many reasons cause packages to lose, like ISP, region, server location, network hardware, or the routes depend on the area, etc.
How fast your internet is doesn't bring equal quality to your multiplayer gaming. For example, What I know is most of the Chinese players using booster or VPN to play Bannerlord because of the server location, no matter how much faster their house network is.
Do you have any Russian friends who have the same ISP and lives in the same city as you? If you do, did they lose packages in the game?
Just like #3 said, that was a simple program to test the capability of your home network to the Bannerlord server. And we can know, Bannerlord is using the digital ocean as their multiplayer server provider.
https://www.digitalocean.com/community/questions/unable-to-reach-digitalocean-server-from-russia
And there is some information showed some Russian ISP probably have bad connections to Digital Ocean data centers.
SO ↓
Did you ever try the booster like WTFAST, which I mentioned before? (I don't know how Game Booster going in Russia, probably using local Russian brand boosters would better, but you should check the game support lists which supports Bannerlord Multiplayer or not.)
I hope you can solve your problem. If you did, please share with us how you solved the issue.