Change openvpn client

[geres]

I want to switch openvpn clients without having to reboot the router every time.
If I switch clients without rebooting I have limited connectivity.
I use nordvpn.

[ncompact]

I assume you are referring to the openvpn client configuration
not the actual software package?

simple:

package: luci-app-openvpn

or

if you must have more than one openvpn client setup
the simplest solution is to save the file:
/etc/openvpn/client.conf
as:
/etc/openvpn/client1.conf (for first time setup)
/etc/openvpn/client2.conf (for second configuration)
etc...

then with a link choose which one to apply

ln -s /etc/openvpn/client1.conf /etc/openvpn/client.conf

and restart the service

/etc/init.d/openvpn restart

OpenVPN client

[ncompact]

nordvpn support wireguard

https://www.google.com/search?q=nordvpn+wireguard