AM5 is working great, thanks for asking! I built the machine exactly as I described - and I'm glad I built it when I did because a few months after I built, beQuiet released new cases and discontinued the case I bought. The new model has some features I don't want and removes some I do (like 5.25" bays).
I had some stability issues with AM5 in the beginning, BSODs - but a few BIOS updates took care of that no problem. Frankly that's to be expected with a new platform, and the ASUS motherboard makes BIOS updates dead simple.
I am using a 27" 4K Dell Ultrasharp which is working well. But honestly I think I am about to upgrade to a 43" 4K TV. Someone at work just put a 43" TV on their desk and it's super nice to have that much space, even at the same resolution as a monitor. I am an elder millennial now so bigger fonts are definitely welcome. Plus TVs have built in speakers so that's one less thing needed on the desk. And big TVs are so much cheaper than big monitors for some reason!
My new desktop is running Cities Skylines 2 quite well, although I don't have any big cities in the game yet. I know with the original that was really when you started to notice performance issues, once population started to rise. It is on Game Pass so if you are a Game Pass member (or if you want to sign up) it doesn't cost anything to install it and try it out!