The only real solution is to make this an extended maintenance task. The batteries are cheap so an alert every 4 years is likely sufficient to replace the battery before it dies. You could do it every 2 or 3 years instead at your discretion.
Dunno enough about ipv6, wouldn’t my ISP still need to allow it?
That’s my understanding, and there’s no option in their locked-up router to enable it, for ipv6 either.
I used a pi 3 to host a Foundry server (TTRPG software).
I use Docker to simplify things, since I run two instances of it. Simple port forwarding setup within the docker container. the main reason I used a pi instead of my computer is so my players could access their dnd stuff all the time.
I stopped because I switched ISPs and they won’t let me port-forward. My vpn supports it but the latency isn’t ideal. I host the same thing through a cheap server now.
Well they still have a finite life and are less replaceable than a battery. Even if it quadrupled the lifespan (which is a reasonably generous estimate given OP’s 4-year duration and wikipedia telling me supercapacitors last 10-15 years), it would still eventually need to be replaced and that would generally require resoldering it.
I think a much better solution is 2 battery slots, one to be a backup battery, unused, and then when needed, an LED on the mobo can be turned on. Honestly OP could jury-rig up a similar system if he wanted to, although it’d be a bit ugly and anytime something is jury-rigged I don’t really think of it as reliable.