After a while the browser starts to lag

[Admini]

I don't use antivirus, the built-in antivirus from Windows is also disabled. I can no longer see the date of the last entry in history, but I doubt that I downloaded 5000 files in 3 months. Was there any way I could turn off automatic cleaning?

No, the 3 months limitation is hard coded in Chromium.
There is some discussion:
https://www.reddit.com/r/chrome/comments...r_then_90/

Are you using Google account sync?
Maybe the download records contain the records from other computers.
By the way, have you ever shut down your computer abnormally?