Self-hosted sync options safe enough without VPN

Lounge
1

I know VPN is the safest option. But bringing it up and down on the phone to sync notes is an additional hassle I am trying to avoid.

I am thinking about 3 options but I am not sure which ones are safe enough to be exposed to Internet.

  1. Joplin Server
  2. NextCloud
  3. Minio

Also I am not sure if any of these three options are mature enough to be used without too much trouble.
I need your help.