If you’re only interested in locally streaming you really can’t go wrong with Kodi and samba shares. It’s tried and tested and has a way longer lineage than jellyfin. I’m a big fan of jellyfin and have it set up; but if I’m on my network I’m more likely to break out Kodi and stream on smb, or even just use VLC. Fewer issues generally.
I remember Kodi from the XBMC days, how much has it changed in recent years? I remember when people started selling "Kodi sticks" way back when that were USB sticks preloaded with openelec and had a bunch of pirate streams preinstalled that were pretty much garbage, and it severely tarnished the Kodi/XBMC name.
It will look very familiar to you from the XBMC days. I’ve been an XBMC/Kodi user since the days of soft modding original Xboxes — they’ve very much melt the same soul and the default skin still harkens back to those days. It’s gotten more and more stable over time, and while I’m sure there are still repositories you can add to add pirates streaming sources, I generally don’t touch those and use it as a “play anything locally” tool. If that’s what you need it for — loading up media from smb or local hdd — it will work great and still plays basically anything you throw at it.