Yeah yeah, theory and practise, of "don't store data on" ...

I wouldn't trust any test you perform, in short.
That's what I thought, grrr

It is an Evo 870, and I found this claim about power surges in several places.
Anyway: I made a USB boot stick from here:
https://www.system-rescue.org/This, alongside gparted (when starting into xfce desktop) to check what /dev/sd* drives actually arte that you are messing with,
the image also contains the savior program:
ddrescue.
I wasted some weekends trying to copy stuff with totalcommander on windows (it's better than windows explorer at least!) and fopund myself un/replugging the hard drive frequently in case of USB-SATA adapter, because after one read error, I thought so anyway, the SATA controller must have striked, as all further reads were errors, until power cycle.
Now on internal mainboard SATA it did the same, and whether I tried this in Windows or Linux, didn't matter.
Clonezilla in "rescue" mode did not help that (although otherwise a nice tool).
So I thought no magic program could read the data without laborious, manual intervention - if it's at the level of the controller not playing along anymore.
But wrong! Ddrescue copied 99,99% of the data in 2..3 hours, apparently bypassing OS filesystem stuff, and all the retries then (that could damage a mech drive so you won't even get the easy data - smart order!

), which took another 10 hours or so.
Ending up with 20KB worth of bad data of 1 TB, that's fair. Spread, of course, so there will be a bunch of files with one to a few wrong bytes or so.
But the bulk of the data is saved.
Also notbale I found that on that laptop, CrystalDiskInfo claims the drive was still 99% good (I guess determined from how much was written),
but on the SATA connector of another PC, it said 60% good, argh! That's quite a bit different.