Dell XPS 9440. Worst keyboard I've ever seen on a Dell laptop. I'm not a fan of the MacBook keyboard either, and this is worse. The touch-activated F row makes accidental activations of Delete / Insert too easy. The flat keys are harder to distinguish, making accidental activation of caps lock a common occurrence. It was a work laptop and so fortunately I didn't have to pay for it.
Personally I'd say my most regretted purchase was the Brand New Model F Keyboards "ortholinear" - It's modeled after an ErgoDox but critically both halves are not connected, so in reality it's two separate keyboards. I don't know how anyone could release something so useless for ~$700. I'm sure all of their other offerings are great, however.
The Dell XPS line I have bought once and will never buy again. I believe mine was a souped up 92xx. Less than a year later the battery bloated for no reason. Put another one, bloated again. Turns out there was some manufacturer issue with the charging unit in the motherboard and by that point it was out of warranty.
I will never buy another XPS. For all of apple's faults, with the exception of the 2018 model pros, I have never had much of a problem.
I too had the battery bloat issue back in 2020 with my XPS. I won't be buying one ever again.