So at this point I think it's safe to draw the conclusion that Envoy Express' overly thick thermal pad might have caused the problems.
TL;DR version:
The thermal pad might have caused SSD to bend and if there are chips on the back of the SSD, they might get "desoldered" as the SSD heats up. If you have a double-sided SSD, either avoid Envoy Express or use without the lid.
In my case the SSDs that worked:
WD Blue SN550 1TB (single-sided)
Intel 660p 2TB (single-sided)
Samsung SM961 (single-sided)
Sabrent Rocket
Q4 4TB (double-sided with empty space on the back)
What died from the enclosure:
Sabrent Rocket Q 4TB (double-sided)
Corsair MP440 4TB (double-sided)
The author of the original post had a Sabrent Rocket 2TB, assuming it was the TLC version, it's double-sided with no empty space on the back.
(Hypothesis) How an SSD dies,
1. The thermal pad of the enclosure applies excessive amount of pressure onto the front of the SSD, causing it to bend
2. The SSD heats up when it is in use, slightly softening the solder on the SSD
3. Some connectors on the edges of the chips on the back of the SSD get desoldered due to the force caused by the bending and the softened solder
It was a great mystery that two 4TB SSDs were killed by the enclosure while the Sabrent Rocket Q4 4TB works just fine, until I realized it has a large empty space on the back. Looking at what worked and what have been killed, all of this started making sense to me.
If you are using a double-sided SSD with Envoy Express,
remove the lid immediately. Your drive might encounter thermal throttling more frequently, but it's better than a dead drive. I personally don't recommend using this enclosure with a double-sided SSD with sparsely packed back side. It might work today but who knows at some point the metal fatigue might throw the last straw. What really scares if that data can easily be recovered by reflowing the SSD, so you return a drive thinking it's totally dead and there is nothing you can do, but other people can just get your data.
As I mentioned the OWC Envoy Express has at least two revisions, but the thermal pads are of the same thickness. Don't expect the 1.0 revision can eliminate the issue. I will try to contact OWC to signal the issue and hope they come up with a newer revision to either have a thinner thermal pad or provide swappable thermal pads with different thickness.
Here are some photos to illustrate what drives are safe to use (green), what might work in short term (orange) and what should be completely avoided.