Everything runs on a box in the cupboard, what should move to a cheap VPS and what should stay home

The line I use is simple: anything another human depends on lives on the VPS, anything large or private lives at home. Your git host, the status page and the two apps friends use are all tiny, so a small VPS holds them comfortably and they stop caring about your power company. Media and photos stay home because they are big and because you do not want six terabytes of family life on rented hardware anyway. That split usually surprises people because it puts the cheapest things on the paid box and the expensive things on the free one, but it is sized by consequence rather than by bytes.

The pattern worth knowing is the split where the VPS is only a front door. Run the reverse proxy and TLS termination on the VPS, connect back to the house over a tunnel, and serve the apps from the machine at home through it. You get a stable public IP, no ports open on your router and no dynamic DNS misery, while the actual compute and storage stay in the cupboard. The costs are honest ones: every byte served now goes out over your 40Mbit upload twice in effect, latency goes up a little, and when the power goes out you are still down, so it solves addressing rather than availability.

Whatever you decide, the thing that stopped my equivalent setup being embarrassing was not moving services, it was uptime monitoring and a UPS. A cheap external monitor that texts me when something is down means I find out before my friends do, and a small UPS covers the brownouts and the ten minute cuts that make up most outages, and gives the box time to shut down cleanly on the long ones. That was a fraction of the cost of moving anything and it fixed most of the actual pain.

Public and small goes on the VPS. Big and private stays home. A UPS and a monitor fix more than any architecture change.

Politely disagreeing with the whole premise. It is a hobby project used by a handful of friends, and downtime is fine. Tell them it is a home server, put a sentence on the status page saying so, and spend the money and the weekends on something you actually enjoy instead. I ran the tunnel and the VPS and the failover for two years before admitting nobody had ever complained about the downtime except me.