Running the installer for steamos, bazzite, nobara, or cachyos should take no longer than 20ish minutes or so... Steam and bazzite will work with no additional setup or config, cachyos and nobara might takes another 20 minutes once installed to finish up installing steam or obs or whatever else you need/want....

I'm bad at PC building, so that took me about 2 hours to assemble and fire up for the first time.... But if you've already have a PC or boight a prebuilt, you don't need to worry about that step