WiFi repeater / 4G hotspot

I would like to use the phone as WiFi repeater and occasionally 4G mobile hotspot.
I assume I should not have problem to setup the WiFi hotspot for 4G mobile network.

However, in most situation I would connect the phone to other (eg public) WiFi networks and share the connectivity on my private WiFi with my other devices through firewall and filters/guard.

Any experience or suggestions for WiFi repeater or hotspot?

This is just an update if anyone wants a similar solution:
The openvpn from extra repositories works fine and the phone will connect and maintain VPN connection.
So far I have not managed to get NetworkManager in Settings, which is probably due to XWayland issue as I had a similar problem with settings for Displays.
Consequently I had to setup and configure the openvpn and networks in CLI, which is not easy on such a small screen without keyboard.
Thus I am looking for GUI solution which would be easy to use on touch screen. I am also looing for filters or guard solution which would work on the phone.