Just curious, but Wouldn’t you call a NMVE enclosure with TB3 or 4 a sufficient ZIP drive reencarnation?

We are looking at $149 for 4TB SSD. That is close to affordable. The only problem is current NAND price are abnormal and I dont expect this price to last. So that is the first problem, price / GB isn't quite there yet.

2nd being NAND quality varies a lot and are not battle tested as long term storage solution. Would I still need to have ZFS Storage for my SSD just in case? If so why not use HDD instead?

May be NAND will get there. But judging from the industry roadmap I have seen it wont happen for another 5 - 6 years.

No. Flash memory loses its data after just a few years unless regularly scrubbed an re-written (which in turn burns through your write cycles).