Final results from my end. Tested OPTune, but did not give me better results. AutoTune PIDs have been better on my end.
Due to "overpowered" status, I changed the props from 5045 to tri-4045. Much more smooth on the throttle now and hovering at 40%. Did a re-autotune. Completely happy with what I have, now.
Just to report: test, try, re-tune, change, google something, test, try, re-tune ... until you found your own stable settings; this is what I learned during the last weeks. There is no "golden" way for settings. But it is fun and has a good learning curve. Thanks to all who helped me here so far!