Neat! I briefly tried digitizing some old VHS tapes for my family. I was just planning on giving them the files, maybe putting it on iCloud, it's a much smaller collection (and I don't have a NAS already!). I did a few, the time investment was the biggest issue, as well as figuring out the right encoding so as to not take up a ton of space, but still be compatible with everyone's (Windows + Mac) native video players while preserving video quality.

On the professional end of digitizing old libraries, I've seen it all. They have cart systems that will automatically load a tape deck, the tape deck rewinds the tape, the system plays the tape while digitizing from the beginning until the end of the tape or end of control track. Once it is done, the tape rewinds, ejects and the robot removes the ejected tape and starts over. This is great for cassette based formats. For reel based formats it still involves an operator threading the tape and changing the reels. Even with the automation, it is a chore.

You could look into one of those VHS to DVD systems. Sure, it's SD MPEG2, but the source was a VHS. At least you're not tying up your computer system to do this. It also means not needing a NAS.