I begrudgingly allowed my S9 to be updated. I normally block all updatesso the phone remains as usable and bloatware free as the day I purchased it. Lord only knows what possessed me to allow the Android 10 upgrade, maybe the result of toomany scotches the night before.
The S9, to me, has never been a good phone. I opened my desk drawer many a time to catch a view of my old S7 manual wishing I'd not sold that on. Throughout the 2 years (almost) that I have had the S9, I find it a frustration to use . Now to add insult to injury, Android 10 takes a rubbish phone and makes it 10 times worse. Perhaps thats what the 10 refers to, who knows, or perhaps using the old androud naming convention the Q means quit whilst you are ahead.
I have a partial solution though and even though Samsung will void my warranty 48 days before it expires, I have chosen to wind back my android insrallation to the days whn I bought the phone and install Android 9 on it again.
My next phone will definitely not be a Samsung, in fact, I may even jump ship to Apple.
If you haven't upgraded to Android 10, the don't. If you have, I'm sorry to hear if that but searching google with 'downgrade my S9 to previous Android version' will show you the way forward.