I don’t run Jellyfin, so take this as is. From what I understand tho, Jellyfin does take a fair amount of resources to run in an ideal situation. Meaning it takes some RAM for multiple simultaneous transcodes, several users, large libraries, etc. A lot of the cheaper Stick PCs come with less than stellar specs. The Stick PC I just randomly picked because it was 8 GB RAM is a MeLE Business Grade PCG02 Fanless N100 Mini Stick PC 8GB. IT retails for $350 USD. For half of that price, you could opt for an SFF Optiplex, bump the DDR3 RAM to max the mobo, and DDR3 is fairly cheap, and still have resources to run other Docker containers if you wanted. For example I run an Optiplex SFF with the i7-4790 chip and 32 GB DDR3 RAM. Currently I have 53 total containers running and it really doesn’t break a sweat. Total cost of the box plus RAM was about $175 USD.

If you are going for the portability aspect, that’s where I think a Stick PC would function best. All that being said, you have options just depending on what your criteria are for running Jellyfin.