I'd drop in an old Nvidia GPU for transcoding, anyway. There's lots of old cards that support nvenc. Don't neglect the Quadro cards, either. Lots of them are cheap on ebay and will transcode just fine without even needing their own cooling fan.
I've been using my AMD 5600G's iGPU to do hardware decode and encode in Jellyfin and it works pretty well. Only downside is that it doesn't support AV1, but it works well with H264 and H265.