I’d argue you could sell the ps5 and the games and make enough money to mostly (possibly entirely) cover the cost of building a more versatile device, but it’s also a bit of effort when you already have a setup that works for you
Edit: also, the system we’re talking about should comfortably run 1440p60 for the foreseeable future. Newer flagship hardware is targeting higher resolution and much higher frame rates.
If you buy parts that are a couple of generations older there is absolutely a middle ground between the ridiculous new GPUs and the steam deck on performance, that you could probably build for a similar price to the deck. I would aim for an AM4 build to take advantage of how cheap ddr4 RAM is, with a 3xxx or 5xxx Ryzen CPU. Something like the 3080 is a great card for a cheap price but I personally would go for an AMD card. A few hundred extra (again in AUD) gets you a good 7800XT which is a pretty damn beefy card, but might be better to drop down a couple of models to save on power consumption.
Going even further, you can take someone’s ATX PC secondhand, swap out the motherboard for a smaller form factor and slap it in a little case.
As for OS, if you want it to be exactly like the deck you could run Bazzite, but SteamOS is either available, or about to be available.
I’ve gotten a CalDAV server, audiobookshelf, and selfhosted obsidian live sync running on my laptop while I wait for movers to bring my shit to my house. Then gotta migrate it all across to my mini PC afterwards. Doing a modular NixOS setup to replace/complement what I used to have running on proxmox.
Once everything is on a dedicated machine I’m going to make a nice little homepage for it, inspired by a previous thread here.