I wouldn't go as far as to say the S21U "clearly defeats" the iPhone. It certainly has a bunch of features that I wish my 12 Pro Max had, but the iPhone still has a few points besides the ecosystem where it tops any Android phone in my book.
One little thing for example that never ceases to add a silver lining to my everyday life is the reader mode on Safari. I worked endlessly with my OP6T to set up an equally good reader mode which would work just as well also in dark mode but I was never able to, and that's one feature I really live and die by given how much I use it.
But yeah at the moment I'm starting to get the Samsung/Android itch again. I've tried having two phones side by side but that never really worked out well. What I'm hoping for is a new take on the iPad Mini with slimmer bezels. That's something I could bring along basically everywhere and use for all the things the iPhone does better, including access to iCloud, that reader mode, etc. While using the Samsung as my daily driver phone. Maybe next year, if the iPad Mini gods smile.