rumblebeard issue

Sorry, I may have missed it or not noticed, but I will make this post.
I myself have been playing since 2020 from steam. No problems whatsoever, no cheats used. in 2024 on epic games free giveaway I get the game chilvary 2. In it I just constantly caught the error: “Anti-cheat protection not active(nullclient)”. Since then, I can't log into any session in the sea. I get thrown out with a rumblebeard error.
Attempts to get through to support are reduced to only one thing - make a clean boot. If I do this, nothing changes, only problems with launching steam. The eac service can't start by itself with error 84 “parameter set incorrectly”. When trying to restore eac from sea installation files absolutely nothing happens, no window opens, not even the screen blinks, task manager does not see opening such a program.
All support advice is to do a clean boot or format the device. I will not format the device, as it stores quite important for me information + programs.
I'm asking for help from the community and moderators, as support just can't or won't do anything.