I'm having DNS issues in macOS Big Sur. I described the issues here: https://developer.apple.com/forums/thread/670856

There's one thought I'd like to add: The issue is very annoying, since the stated procedure is most probably not the only way to trigger this issue. I work all day with my Mac and at least once per day I have to reboot.

I already filed a bug report: https://feedbackassistant.apple.com/feedback/8963072. The sysdiagnose file is attached, however the profiles you mentioned where not enabled at the time the sysdiagnose file was created. Referring to your comment "That is odd, especially if this is only happening with Samba", there's an additional thought I already posted here replying to my own initial post: https://developer.apple.com/forums/thread/670856?answerId=655592022#655592022