You should give Bazzite a go on your desktop, it's very similar to SteamOS and the desktop experience has been great for me. I didn't have a Steam Deck and transitioned to it, and the smoothness convinced me to get a Lenovo Legion Go and install Bazzite straight OOTB.
It makes more sense to build a new PC than it does to just change OS on this.
I haven't made comparisons with gaming, tho I know there is somewhat, but there's been a big performance boost on desktop and regular applications running Bazzite over Win10.
You should give Bazzite a go on your desktop, it's very similar to SteamOS and the desktop experience has been great for me. I didn't have a Steam Deck and transitioned to it, and the smoothness convinced me to get a Lenovo Legion Go and install Bazzite straight OOTB.