"The biggest mistake I made was high uptime"

Quite. I'm old enough to remember machine uptime being a badge of honour.

However, being older and not really wiser, I look for service uptime these days. Yes we did have similar back in the day, that's why MX and the like DNS records exist.

Old school clusters were pretty esoteric but the lessons were learned (split brain n that) and that's why we still argue the toss with kiddies about why a Proxmox cluster with two nodes is fucked and why we recommend an additional "witness".

I don't care that VMware glossed over the whole two node HA cluster thing years ago with a massive bodge. They were wrong then and they are probably still wrong because that nonsense is probably still baked in.

Sorry, slight digression.

High uptime implies no patching. We all love patching.