Hello
My FP5 is just getting ready fot its third birthday and the main issue I am experiencing is the recent button not always responding
Judging from the lack of follow up posts 
I might be a bit of an outlier here.
I did two factory resets this year (the phone got repaired twice) but these were more of hardware issues (fingerprint scanner, missed loose connector).
If I may, I would suggest more troubleshooting (how old is the SIMcard, do you use the SD card, who’s your provider, have they recently changed the network settings, etc.)