There shouldn't be any problems with that. Here's basically your question: https://www.truenas.com/community/threads/transfer-data-from-usb-hdd-to-freenas-box.24226/
Pvt-Snafu
Agree with the NAS suggestion. Will be more convenient and reliable than a USB RAID enclosure. I would look into Synology if you want a ready solution.
Because of quite high chance of getting an SSD that was overwritten multiple times or an HDD that was used a lot which increases chances of it's soon failure. But again, used drives might not be bad if you're buying from a reputable seller and depending on what you use them for.
For automation, I would look into some proper backup software like Veeam which has free Agent for Windows: https://www.veeam.com/agent-for-windows-community-edition.html. Also, try following the 3-2-1 backup rule: https://www.backblaze.com/blog/the-3-2-1-backup-strategy/. For example, you could add Backblaze Personal cloud.
Well, I was ranting about internet speed being lower than advertised after optics installation which should be 1GbE (I got only 300MbE) until I understood that the Asus router I bought a couple of days before that was just 300MbE.
Honestly, I wouldn't go with Storage Spaces. Just unreliable. If you're willing to take the risks, forget about GUI for a proper performance: https://storagespaceswarstories.com/storage-spaces-and-slow-parity-performance/ Also, no to RSTe. I would personally go with a hardware RAID controller on Windows.
If you have money for an SSD system, then why not? Also, there is no "no need to modify me for an eternity system" as such. Backups and periodic verification is a must if you want to keep your data. No matter HDDs or SSDs. Also, RAID 1 with 4 SSDs? That's only 1 SSD usable capacity. Unless you mean RAIDZ1.
Well, that's a tough question but I think no:) Unless you have multiple backups and want to experiment:)
There should be no problem streaming 4k from HDDs as others said. As to SSDs, depends how long are you going to store them without power but I'd say they will be fine for several moths or even more. Again, backups. Also, I'd run CrystalDiskInfo to check drives health: https://www.pcsteps.com/2530-predict-hard-disk-failure-crystal-disk-info/
How much are we talking about? I mean, Backblaze B2 or Wasabi might be a good option. Or hetzner if you're in Europe.
Definitely not motherboard RAID. However, why not MDRAID (old but gold) or ZFS (protection against bit rot plus all the other sweet features like snapshots etc.)?
I would just avoid SMR drives, especially if you're looking to use them in RAID: https://nascompares.com/answer/list-of-wd-cmr-and-smr-hard-drives-hdd/ . Otherwise, any drive that fits your budget and that is CMR.