How do I Transcode to H.265?

[AlternateWitness]

I have a pretty slow upload speed, and I access my server remotely often, but for some reason when jellyfin transcodes to a lower bitrate it always does so in H.264? I've tried on multiple devices that all support H.265. All of my media is originally encoded in H.265 10-bit and AV1 10-bit. I'm using NVENC to encode my media, and I have "Allow encoding in HEVC format" selected, as well as hardware decoding for HEVC and HEVC 10bit. What else am I missing? Sorry if this is so simple and I'm missing something obvious, but I'm not sure what else I could try. In order to make most content watchable I need to encode it in at least H.265.