Re: MLC and TLC are crap already.. QLC will be the worst really...
Most of the failures we've seen were due to poor SSD firmware and OS support, not the Flash itself.
When a few customers first put SSDs in (against advice), they'd die in about six months because OS support was terrible and SSD firmware poor.
Later, OS support became good and failures instead clustered with particular brands and sizes.
Firmware updates fixed that.
These days, they last very well.
The downside is that they die without warning - sure, the health data makes some claims but most failures don't seem to trip the warnings.