I sold my original Mini as it eventually ended up sitting in a case in a drawer rather than actually being played, partly because the form factor was so small but mainly because of all the reports of broken fragile screens from short drops like 2ft onto carpet.
I recently couldn't resist the temptation to get a $35 MM+ from Temu and now that I have it I have a similar concern- is the MM+ as fragile as the original?
It's probably not going to survive any serious roughhousing, but it isn't especially fragile. I know that some people have had issues with the screen where they've stuffed a case with USB leads and adaptors and had them push on the screen, breaking it. But you'd expect that.
Overall, it feels pretty well made. Way above your usual cheap Chinese junk, somewhat below something premium like an Analog Pocket.
I carry mine around in a small bag. I was a bit concerned about the screen getting wrecked, so I 3d printed a screen cover, lined it with some felt, and it just slides on. Works well.