I’m feeling with you. I’m one of the first owners (ordered 7/2015, received 1/2016) an went through several issues. I’m OK with an unusable phone while charging, I fixed the frequent reboots by fitting a piece of paper underneath the battery. Actually, it’s kind of cool to fix a smartphone by inserting pieces of paper 
But things have gone worse recently. First of all, the touchscreen has behaved strangely for a couple of months. I thought this has to do with the connectors between main module and screen module, and were somewhat successful by adding further papers in between the case and the core module to increase the pressure on these contact. It however got worse, such that I can use it about 20% of the time. The remaining time, the screen would not react or just show me colored pixels. On top of that, mobile connectivity has been almost completely gone ~2 weeks ago. This means that even if the screen works, I can’t make calls (this is still a PHONE) within closed rooms.
So far, I’ve always given a recommendation to buy a FP, but I’d now definitely abstain from that. Maybe support will help with this, but certainly not quickly.
Meanwhile, I’m going for a backup motorola…not the ressource-friendliest way, I assume.