Samsung Portable SSD T7 – Only seeing trim action on 1 of 3 similar SSDs

We are in Sequoia on a new M4 Mini. Decided to do speed tests on our 3 external SSDs, which are connected via a USB2 hub (but we see same results when connected directly).

Trimforce is set ON.

SSD#1 is T7 Shield 2TB. GUID, 10 Partitions, all MacOS Extended Journaled. Data volumes.

Write/Read ~775 / ~600 MB/s 24 months old.

SSD#2 is T7 2TB. MBR, 10 Partitions, all MacOS Extended Journaled. Backups of #1.

Write/Read ~100 / ~600 MB/s 16 months old.

SSD#3 is T7 Shield 2TB. GUID, 3 Containers, all APFS. Miscellaneous OS versions.

Write/Read ~800 / ~600 MB/s 14 months old.

When we run Disk Utility First Aid, only SSD#1 shows "trimming unused blocks", 5 lines above completion.

We are guessing that the lack of trim actions has slowed SSD#2?

And that trimming is simply not reflected in that process for APFS on SSD#3?

When new, SSD#2 had after performance like the other two.

Is it time to wipe SSD#2 (and maybe change to GUID?)

Or is there a way to force trim, from a different environment?

Thanks for any insight.