I have been using Linux as a desktop operating system for what I believe is almost two decades. Recently(?) I see distro named like CashyOS and Bazzite being thrown around. Am I missing out on something?

There are many really good ones these days that will have a much better experience than windows. I’ve used Ubuntu, Pop, Mint and Fedora workstation in the last 5 years and all worked great. Personally Mint Cinnamon had the least issues so I tend to run that on my machines now.

Once SteamOS becomes generally available I’ll switch to that. It’s incredibly polished on Steam Deck

If you don't want the "hassle" of flag optimization when compiling binaries, CachyOS is basically Arch but with optimized binaries. Otherwise, Gentoo all the way, you just need a good machine.