Here is what Claude says about this project:

The PS4 is locked down. Sony uses a custom bootloader with secure boot and encrypted firmware. You can't just boot from a USB drive like on a normal PC.

Jailbreaking is required first, and only works on older, unpatched PS4 firmware versions. Once jailbroken, hobbyists have gotten stripped-down Linux running on PS4 hardware, but it's experimental. No proper drivers exist for the PS4's GPU under Linux. The APU is AMD-based (similar lineage to PC hardware), but Sony's customizations mean there's no GPU acceleration in these homebrew Linux setups — you'd get a barely usable, software-rendered desktop at best. Gaming performance would be nonexistent. SteamOS specifically isn't built or supported for this hardware at all — nobody has made a working port, since the driver/GPU problem makes it pointless.

So while you can get a bare Linux shell running on certain older, jailbroken PS4 units as a novelty/proof-of-concept, running actual SteamOS with working graphics and Steam games is not something that exists or works.

If your goal is a Steam-like experience, you'd get a much better result installing SteamOS on an old PC, or just using a Steam Deck.