@NiwlCraft If ARM is not a strict requirement, I can highly recommend the ASRock Intel N100M. Throw in up to 32 GB DDR4 and some storage (M.2 NVMe or SATA) and put it in any Micro ATX case. I have mine in an old server case with a pico PSU for fully fanless operation.

It's powerful enough to run Jellyfin (with hardware encoding), Immich, Homeassistant and a few other things at the same time.

If you ever need more storage, you can add a PCIe card for more SATA.

https://www.asrock.com/mb/Intel/N100M/

@NiwlCraft There is also a Mini ITX version that works with a DC barrel jack power supply: https://www.asrock.com/mb/Intel/N100DC-ITX/index.asp
ASRock N100DC-ITX

Intel Quad-Core Processor N100 (up to 3.4 GHz); Supports 1 DDR4 DIMM; 1 DC Jack (Compatible with the 19V power adapter, 5.5 x 2.5mm DC-in jack); 1 PCIe 3.0 x4 (x2 mode), 1 M.2 Key E for WiFi; Graphics Output Options: D-Sub, HDMI; 7.1 CH HD Audio (Realtek ALC897 Audio Codec); 2 SATA3, 1 M.2 (PCIe Gen3x2); 4 USB 3.2 Gen1 (2 Rear, 2 Front); Realtek Gigabit LAN; Supports ASRock Auto Driver Installer