Do you know if it’s hardware or software issue? If it’s software, you can make a steam recovery drive and fix it that way. There are options to re flash everything or just repair steamOS system files. You can actually get stuck in a boot loop by maxing out the internal storage, so it might be worth booting into recovery and deleting some files if you think you’re close to maxed out.

As a cautionary warning, the SteamOS recovery media doesn’t properly support wifi 6 on the OLED deck, and might crash the wifi card, requiring you to reboot and start over. If you’re on an OLED deck and your router supports wifi6, I’d recommend only connecting to the 2.4GHz network provided by your router and not the 5ghz one to avoid this. Ethernet is also safe if you have a dock.

If your issues are hardware based, you can still send it into valve and they’ll give you a quote on the repair cost. Obviously it will depend on what’s wrong, but I usually hear of people getting pretty fair repair quotes.