You don’t need SteamOS to play games via Steam on linux. Just use any linux distro (preferably one that supports newer gaming hardware), install Steam, go to Settings > Compatibility and “Enable Steam Play for all other titles”. There’s a drop-down that let’s you choose different Proton Versions (some work better than others, hence the config-reviews on ProtonDB to see what works).

For gaming you can just use steam. You can see which game works and the corresponding distributions/configurations on ProtonDB; Helldivers 2 get’s a GOLD status (https://www.protondb.com/app/553850).

I bought a Portable Power Station (e.g. Anker SOLIX C300) to use as an Uninterruptible Power Supply (UPS) for my homeserver (~ 40 Watt) to buy me - or better my utility company - a few hours in case the power fails.

:)