Impressive that all that can run on one machine. Mind sharing the specs?
It's an i7-4790k from 12 years ago, it barely breaks a sweat most hours of the day.
It's not really that impressive, or (not to be a jerk) you've overestimated how expensive these services are to run.
They recommend 1GB RAM per 1TB storage for ZFS. Maybe they mean redundant storage, so even 2x16TB should use 16GB RAM? But it's painful enough building a NAS server when HDD prices have gone up so much lately.
The total price tag already feels like you're about to build another gaming PC rather than just a place to back up your machines and serve some videos. -_-
That said, you sure need to be educated on BTRFS to use it in fail scenarios like degraded mode. If ZFS has a better UX around that, maybe it's a better choice for most people.
Otherwise, the only benefit more RAM gets you is better performance. But it's not like ZFS performs terribly with little RAM. It's just going to more closely reflect raw disk speed, similar to other filesystems that don't do much caching.
I've run ZFS on almost all my machines for years, some with only 512MiB of RAM. It's always been rock-solid. Is more RAM better? Sure. But it's absolutely not required. Don't choose a different file system just because you think it'll perform better with little RAM. It probably won't, except under very extreme circumstances.
Not GP but I have lots of fun running VMs and lots of containers on an old HP Z440 workstation from 2014 or so. This thing has 64 GB of ECC RAM and costs next to nothing (a bit more now with RAM that went up). Thing is: it doesn't need to be on 24/7. I only power it up when I first need it during the day. 14 cores Xeon for lots of fun.
Only thing I haven't moved to it yet is Plex, which still runs on a very old HP Elitedesk NUC. Dunno if Plex (and/or Jellyfin) would work fine on an old Xeon: but I'll be trying soon.
Before that I had my VMs and containers on a core i7-6700K from 2015 IIRC. But at some point I just wanted ECC RAM so I bought a used Xeon workstation.
As someone commented: most services simply do not need that beefy of a machine. Especially not when you're strangled by a 1 Gbit/s Internet connection to the outside world anyway.
For compilation and overall raw power, my daily workstation is a more powerful machine. But for a homelab: old hardware is totally fine (especially if it's not on 24/7 and I really don't need access to my stuff when I sleep).
It does have 16 spinning disks in it, so I accept that I pay for the energy to keep them spinning 24/7, but I like the redundancy of RAID10, and I have two 8-disk arrays in the machine. And a Ryzen-7 5700G, 10gbit NIC, 16 port RAID card, and 96GB of RAM.
In my case I fell in love with the tiny/mini/micros and have a refurbish Lenovo m710q running 24/7 and only using 5W when idling. I know it doesn't support ECC memory or more than 8 threads, but for my use case is more than enough
I do have a bit more than just that server hooked up to it. There's also a Dell i5 running DDWRT as my main gateway/router, the fiber internet modem, a small Synology NAS, a couple of WIFI routers, etc. It all adds up.
That doesn't include my backup server out in the garage with another 8-disk RAID10 array and an LTO tape drive that is often backing up data, 5 more WIFI routers around the property, and 10 or so security cameras. So I'm probably well over $100/mo for all my tech stuff.
Way way overspeced for what I listed, but I use it for lots of video processing, numerical simulations, and some local AI too.
I have a similar subset of this stuff running at my mom's house on a 16 GB ram Beelink minicomputer. With openvino frigate can still do fully local object detection on the security case, whish is sweet.