I’m assuming you don’t want to tinker with things? I’m also assuming you do not have experience with things like ZFS. So….
Unless you’re running multiple drives (or special options) zfs & btrfs aren’t going to give you much. For instance btrfs (unless it’s set to DUP) isn’t going to protect from bitrot or other data corruption. Same goes for ZFS. It will throw an error when something doesn’t match the checksum though.
Your best option is to either use ext4 or xfs for your 4tb storage. If you’re working with a lot of large files xfs has some advantages but overall you’re not going to notice that much of a difference in your uses.
For your ssd, btrfs has the advantage over ext4 and xfs. Although so does f2fs. In practical uses for what you’re describing it’s not going to make that much of a difference.
Unless you have a specific reason to use something other than ext4 then just stick with that. It’s simple and just works. Make sure you’re keeping backups eg restic, borg, rsync, duplicity, etc etc. and follow the 3,2,1 rule where possible and you’ll be fine.
If it were me setting up that system I’d mirror the drives and use btrfs. Which is pretty much what I did on my PC. But that double the costs of storage.
The only place (at home) I use ZFS is on my NAS. I have Rocky8 setup and all it does is handle storage. I use mirrored pairs on my important data and Z1 on everything else. But that’s a topic for another post
If you REALLY want some of the features of zfs or btrfs eg snapshots, I’d lean on your backup software for that but if you can use LVM to take snapshots in a similar fashion. See STRAIS for another example too. However that’s beyond the scope of this post.