I currently have an older Synology DS412+ with 4 drives (2x 8TB, 1x 10TB, 1x 14TB) in an SHR config for ~26TB of useable storage. I'm at 80% capacity and will want to upgrade soon. I could stay on Synology and replace the three smaller drives with 14TB drives, but the downsides are (1) that would only get me 10TB more useable space, (2) it would waste the existing drives, and (3) the Synology is EOL and no longer gets updates.
I also run a dedicated Proxmox server. It looks like there are a few options to migrate my NAS over there: either setup a ZFS storage pool managed in Proxmox directly and pass it through to a NAS VM like OVM, or add a HBA card and pass the whole thing through to TrueNAS. That's appealing because it gets out of the EOL problem and gives me room to add additional drives in the future, but everything I've read says that you really shouldn't mix different drive sizes for RAID, so the only problem I'd really solve above is the Synology EOL. Plus, even though I'd have the capability to go above 4 drives, it sounds like migrating there isn't any easier.
In terms of usage: The NAS is used primarily as storage for a Plex server, but transcoding all happens on a VM on the Proxmox server. Speed is nice-to-have but not ultra critical and I don't need the NAS to do anything super fancy beyond being a JBOD.
I'm curious what folks here would do. Anyone made a migration away from Synology they're really happy with? Should I just stick with Synology?