Thats why I suggested an up-to-date router that isn't end-of-life. If you keep your router firmware updated, your firewall on, and your "server" updated, then you are as protected as any VPS that has ever been deployed.

Tailscale is centralized and prevents you from accessing your devices if it goes down, which is what the OP points out. If we want some decentralization, we can configure our current equipment to do so. Its not so difficult if you spend some time reading your router's documentation and keep everything behind it updated. NAT firewalls are pretty good at keeping bad things out.