I’ve coincidentally bought this machine for similar purpose, arriving tomorrow.
I’m intending to install a Linux KDE environment on it and use it as a living room PC, steam Linux machine, stream from my PC for 4k gaming, and a Jellyfin /Kodi box. I could probably keep windows 11 on it but I prefer the privacy and control I get with Linux plus it’ll be a fun little project.
Was on sale for £270 here, and looks overpowered for what OP’d need.
Raspberry Pi 5 is also available for like £80 and that’s capable for 4k video (although frustratingly the web browsers aren’t able to take advantage of hardware video accel from my tinkering; you have to use dedicated apps like Kodi, freetube etc). That could also be a viable route for Plex / Jellyfin / Kodi machine media server and player or even just server.
Edit: worth point out a raspberry Pi costs the same as 10 months of just Disney+ without ads. Once you throw in other streaming subscriptions… May pay for itself much sooner…