First of all, my parents have a Raspberry Pi V1.0 (the still holeless one) that has been piholing since day one. That's like a decade.
I keept it there, caseless and dangling from the lan cable, for sentimental reasons, I've grown fond of it.

Second of all, there is a secondary dns on Proxmox should the Pi need a rest.

Edit:
Forgot the third of all - that Raspberry doesn't even have a heatsink, much less a fan.