Lot to unpack here.
I still don’t really understand what you are asking for.
You say that you don’t intend to run VMs but at the same time you say that you want to run Jellyfin? Maybe you could describe your use case a little bit better.
In general, ZFS does not need ECC more than any other file system like NTFS. The bigger issue IMHO is that not having ECC makes troubleshooting bad RAM a lot worse.
ZFS comes with drawbacks!
So for me the question is, if I value my data so much that I am willing to endure the drawbacks of ZFS instead of using something like UNRAID, why should I not use ECC?
IMHO most people also don’t need any kind of RAID. RAID is availability, not for backup! Do you want availability at home? Because if not, you are probably better off with these backup or “fake RAIDs” like UNRAID.
For most home users, having any kind of RAID will increase the risk of loosing data. Simply because hardware error is a way smaller issue than user error.
Here are some other general takes I have on TrueNAS and Proxmox.