Apart from the hardware-needs and the possibility that you need more potent one..
If you really just want a NAS and Jellyfin i would suggest Openmediavault and Jellyfin in a docker-container.
I got that setup myself and i am far from a specialist in any regards.
There is even a guide which you could follow pretty much step by step (https://wiki.omv-extras.org/doku.php?id=...ker_in_omv) [please remove if posting that link is not allowed!]
But - as i said - there are more capable people here to give advice
If you really just want a NAS and Jellyfin i would suggest Openmediavault and Jellyfin in a docker-container.
I got that setup myself and i am far from a specialist in any regards.
There is even a guide which you could follow pretty much step by step (https://wiki.omv-extras.org/doku.php?id=...ker_in_omv) [please remove if posting that link is not allowed!]
But - as i said - there are more capable people here to give advice