Sorry to hear that! I have a pretty low sample size of ~8 friends on FP3 and I can't remember hearing of a single hardware failure. Some batteries got replaced and some are even still going strong on their first battery. I've updated mine from 3 to 3+ and I'm on my second battery since this summer, I.e. the main board is ~4years old. A friend had some minor issues in the beginning with some internal connector but I can't remember him mentioning it again.
Another friend got rid of her FP2 this spring in favor of a FP4, but only because some apps she uses got really unusable. Otherwise she would've stayed.
IMO it's a fairly good platform and I'm looking forward to how it evolves in the future. Hopefully they will introduce a smaller phone at one point.
I had to replace the USB module on my FP3 because it couldn't charge my battery anymore. At first I tried to replace the battery but that didn't work, and I was afraid that the issue would be from the motherboard, but no I just needed to change that module. Great experience!
Another friend got rid of her FP2 this spring in favor of a FP4, but only because some apps she uses got really unusable. Otherwise she would've stayed.
IMO it's a fairly good platform and I'm looking forward to how it evolves in the future. Hopefully they will introduce a smaller phone at one point.