I travel all over the world with an iPhone and laptop. I want to make my Joplin server only reachable by VPN and not publicly reachable. I also want to be behind a VPN service for general internet usage and have a quick connection to the internet so a distributed VPN service could be optimal.
Tailscale will make your server reachable, but Tailscale itself is VPN and it cannot be used together with other VPN on IPhone AFAIK.
I suggest you to research if that’s possible now and if not - what is the workaround.
There’s a “funnel“ concept in Tailscale that you might look at - I assume it makes your configured endpoints reachable from internet but does not expose your whole server, only what is configured.
This way you might be able to use regular distributed VPN like Proton, but also communicate with Joplin Server through Tailscale “funnel“.
Another option I’m thinking about is using a VPS as a middle hop: connect Joplin server + laptop + phone to Tailscale, then use the VPS as an exit node for “general VPN” internet traffic.
If OP wants to use a VPN in exotic countries to circumvent censorship but is fine using their home country ISP without VPN then they could setup any device in their home country as their Tailscale exit node.