As soon as I upgraded to BigSur 11.0.1, I started noticing that some of the UI components in STS 4.8.1 started to disappear (or let's say they don't show up, since as soon as I click in the area, where they are supposed to be located, they start to appear) - this can be observed in the History tab for example. Another issue appears during the Debugging - as soon the execution reaches any breakpoint the screen doesn't seem to be refreshed automatically and the current code line, where the breakpoint is, gets mixed with the previous code lines. EDIT: if I scroll the page (up/down) the screen gets refreshed and I am able to see the correct line.
Initially I thought that this could be due to the DevStyle plugin (the dark mode), but I uninstalled it completely and I tried again and the issues are still present.