Hi guys first of all im not an expert of any thing, but this happend to me aswell and i have a long time doing some test trying to find where is the problem, so i think the problem is the way the information is sent between the server and your pc (you shouldn't have this problems playing in singleplayer or in your own server with 0 ping).
The first problem: this game is old and looks like dont support well the high polling rates of this new mouses (1000hz or 500hz, even with 250hz u can have a bit of lag).Looks like Keyboards polling rate doesn't affect the game, before i used a cheap 125hz keyboard, now i have a mechanical one with 500hz of polling rate but dont make me lag.
The second problem: the higher is your framerate more lag you going to have and more strange things going to happend in your screen, i think this have some relation with the tickrate of the servers, when i host a server in my own pc the tickrate of the server is 100fps with some spikes to 125 so i can imagine the community servers have the same tickrates, but if the servers are just bad or have alot of people inside, the tickrate should be lower. So if your framerate is above the tickrate of the server the game engine have to create some invented-imaginary frames because the server is sending you only 100-125 frames or less, so the game engine just can start to show you some things in your screen that are not really happening in the server or for other players. As i said this dont happend in singleplayer, only in multiplayer at least for me.
Conclusion and solution for me: you have to decrease your framerate, if 300fps make you lag try 200, if keep lagging try 150, 144, 120, 100... But if you want to play at 300+ fps you have to change the polling rate of your mouse to 125hz or 250hz, 500hz going to keep lagging. I dont know if this problem have some relation with the internet or hardware of your pc because i didn't tried other routers or hardware.
Sorry about my english if i make some mistakes writing. Btw here are my pc specs: amd rx580 8gb, i5 10400f, 16gb ram at 3200 mhz, game installed in a hdd and i play with an ethernet cable (10m long)
UPDATE: I was wrong in the second point, i have been doing some test about the connection with the servers and looks like the real tickrate of the servers are around 30hz (client and server packets around 30), the problem come when you are running the game at high framerates and high polling rate in the mouse, this causes that the client packets sent to the server have some big spikes, so become unstable. Probably there are some problems with the interpolation technique of the game as well.