I believe you’ll be happy with an upgrade to Core 2 Duo. I upgraded to a Intel NUC with Pentium and the performance increase, transcoding capabilities and x86 support were awersome. Also, having a SSD drive instead of RPI’s SD card gives a good performance increase.

You’re welcome :)

I needed better transcoding support and switched to an Intel NUC - almost the same power draw, x86 software support and way better performance. But I still use Raspberry Pi for smaller projects and home automation.

I used to have a RPi 4 as a Jellyfin Media Server. I never tried 3-4 simultaneous streaming, but I remember that, if no server transcoding was involved, it could deal with 2 simulteaneous streamings without problems. I used an external HDD also.

On tutorials, Jellyfin’s webpage has a nice tutorial on the Debian installer page (https://jellyfin.org/docs/general/installation/linux). Also, the container version could be a good option.

Watch out for folder permissions so Jellyfin can access your external HDD.

Hollow Knight and Vampire Survivors are the ones that managed got me hooked in the last few months