I rarely build new computers (3570k crew rise up!) but am considering doing so on the AM5 platform. I am considering jellyfin or plex on this new rig and streaming to my tv and to my phone and laptop.
The question is, do ryzen chips support hw acceleration for this? I don’t want to put a gpu in the new rig but am willing to spend on a “beefier” apu if needed. I have never used jellyfin or streamed video so I don’t know what typical compression is used or if that even matters.
They do. 
I’ve had both Jellyfin and Plex use the iGPUs on a Ryzen 5000-series mini PC (5600H, specifically). Far as I know, all of the 7000-series chips have an iGPU in them so those should work as well.
Jellyfin docs for it:
Plex doesn’t officially support AMD GPUs because, per their docs anyway, they can’t be bothered to test it. But it can work.
Edit: Oops, missed part of the question. As far as the video compression part goes, the GPU will have support for certain video codecs. If the files you are attempting to play aren’t one of those codecs, it will fall back to trying to use the CPU to do the media stream. It will only do transcodes though if the end client device can’t play the file itself via direct streaming, usually. More details here:
Welcome to the forum, btw!
Imagine how the Gpus have been out for 7 years now with full video acceleration and Plex team can’t get around to testing them. Literally amazing the level of complacency.
Hardware acceleration is available, you can just get by with a VPN (if you’re not at home) and SMB shares for your laptop and phone which will retain quality a lot better. As for your TV a cheap media player running LibreELEC is probably less hassle and will just work just fine.