I’d wait until @HoneyBadger replies.
I’m not too familiar with how finicky ZFS can be when (intentionally) attempting to import a degraded pool. (The only time I ever intentionally imported a degraded array was with mdadm on Linux, and that was a while ago.)
Here’s another case of something similar happening.
My hunch is that this same problem is what affected two other users as well, but they had since moved on and wiped the drives, so it’s too late to know what the underlying problem was with them.