I had a recent crypto mining adventure that used of SSDs and ran them flat out for days moving about 30 TB of data in a day.
SSDs can consume a considerable amount of power indeed, but its still less than a HDD. An actively working SSD does consume more than a idle HDD (laptop drives typically reduce RPM when under low utilization), but when a HDD is actively working it consumes more power than a actively working SSD. Still these powers are in the order of a few watts, so its not going to really break anything.
What i have noticed however is that hammering a bunch of SATA SSDs full on did make the southbridge run noticeably more toasty (This is where the SATA comes from) so i added a fan to help cool it.
Modern SSDs can indeed saturate a PCIe link because they typically only use up to a PCIe 4x link. Yes GPUs can transfer even more data since they have a PCIe x16 link while they indeed don't usually make use of all of it, the trick to making the GPU hog all of it is to let it run out of VRAM, this will make it start swapping into main RAM and clog that x16 link. But this is unlikely to make something overheat, if anything a big GPU itself would cook things to death before the PCIe power use would, the PCIe lines go straight to the CPU anyway. However... there are also chipsets out there that provide extra PCIe lanes from the southbridge chip, these are typically used for any extra onboard peripherals such as perhaps a fancy high performance network interface, WiFi, extra SATA controllers, and M.2 slots. So in this way a M.2 NVME SSD could put extra thermal load into the southbridge chip.
An SSD will also rise the peak CPU utilization since during boot the OS is spending much less time waiting for data to arrive from disk and much more time actually processing the data it just read. But a laptop should not die just because the CPU utilization hits 100% every so often. That's like a cars engine breaking down if you floor the gas pedal for a little bit too many times. But yeah holding 100% CPU utilization on a laptop tends to not be good for them since they typically don't have enough cooling to handle it unless you live in Antarctica. But this is not something a SSD would do.
I don't really think this is the cause of the machines giving up the ghost. Its likely just that they die from old age. All the machines you happened to upgrade ware likely machines that got used a lot (hence why they ended up upgraded) and they just slowly died on there own. A lot of apple laptop models are famous to just die after a certain number of years due to the soldering giving up.