A thing that helped me were some console commands.
rate 25000
cl_cmdrate 101
cl_updaterate 101
ex_interp 0.01
Hope this helps
My understanding of these commands is that they need to be configured for the server you are playing on, not what your PC can do.
I frequently see these suggested and use them myself. I did, however, reduce cmdrate and updaterate to 67 as the tick rates on most servers is 66.something now. 33 on others.
I set cl_interp (I haven't tried it as ex, this is the first time I've seen it typed that way) based on the rough average of my latency to that server. I don't need to change it much between eGO servers, I get about the same across the board. I get about 75ms on average so I set it to cl_interp 0.075. It cleaned up my reg quite a bit.
rate XXXXX is another setting I see recommended for use quite a bit, often inserting or suggesting a generally really high number. I haven't set mine in a while, but I know I used the speedtest website to benchmark my bandwidth and set the rate accordingly.
A lot of people see commands like these on the internet, primarily with the values changed to be significantly higher than original and many see benefit from it. I have, personally. The more I read, though, the more I found that with a little work on your part you can set them very accurately to your specific setup to get optimal game-play.
They do generally work quite well for people to just plug in and get noticeable results, though
I'm trying to put together a list of my preferred tweaks for this game because all of the ones I find come up just a touch shy in some category or another. Most of them on explanation alone. Few people take the time to explain each command and how they work and just offer some blanket value without describing how you can find what will work best for your setup.
Good work tracking down the issue. A lot of people give up on a game or sometimes gaming altogether over issues like that.