@Frieg
Out of interest I tried to replicate your result, using an M4 Pro mini and an M1 mini.
I don't get the same result.
Connecting two different USB 3.1 Gen 2 10Gbps enclosures with a Kioxia or Samsung NVMe 1TB SSD inside,
I get BlackMagic (5GB file size) connection R/W speeds of 750-850MB/s in all cases using the TB5 or TB4 ports of the minis, and also from the front USB-C ports on the M4 Pro mini.
Only using the USB-A ports on the M1 mini does the speed drop to below 400MB/s, but Sysytem Information still reports 'up to 10Gbps'.
So it may be the USB-A to USB-C cable I'm using, because it came from a 3.5" HD enclosure, so it may only be USB 3.0...
The enclosures I'm using all have RTL-9210B-CG controller chips, and the OWC Mercury Elite Pro mini enclosure you mention is using an ASM235CM chip.
More importantly, that enclosure is designed for a SATA 3 2.5" SSD, which can never reach 10Gbps speeds, so maybe using a 5Gbps cable?
The problem you have may be specific to your particular situation.
This original thread post was noting the problems with M1 Macs in the Big Sur era.
You berate Apple for being
'lazy' and
'pathetic', 'or don't want to implement the standard'.
You also say
"That's not the point of this thread." about the post from
@ubercool about the increase of TB4 peripheral speeds when connected to a TB5 Mac.
I see the two as interconnected.
If Apple hasn't managed to rectify a USB 3.x connection problem, my guess is that it could only be solved at the expense of the proper working of the high speed TB4/5 ports.
That is the real world we care about today.
USB 3.0/3.1 hasn't really worked as a 'standard' that is backward compatible, and Apple has only looked backwards when it doesn't impede 'going forward'.
So complaining about this isn't going to make a difference, we have to live with this. 😉