I've said this before, but it's worth repeating...
If you use Raspberry Pis on any kind of mass scale, learn about and use the built-in Broadcom watchdog timer.
It has completely mitigated any inherent instability in the Pis I run as PAC kiosks. I've had almost 80 of these things (mostly 3B+) running 24x7 across several locations(some in children's areas) for over a year,and I've only had to physically touch one one time, and that was because there was a key on the keyboard physically stuck.