Recovery Mode seemingly has flaws. If it is active and I try to activate a plugin within recovery mode - each plugin appears with a link to do so while in recovery mode -, then .... nothing happens. The plugin remains inactive.

Another hint: if you follow PHP version recommendations and go for 7.3+ you are likely to receive errors in tests like wtih Query Monitor as code switches ending with "continue" are regarded faulty. It's either "break" or "continue 2", so plugin authors got some work to do.