VPN network - transform external script to native service

I'm trying to setup VPN -
One NetGear R6220@OpenWRT_23.05 as a main router at home and VPN server and another NetGear R6220@OpenWRT_23.05/GSM as a remote router and VPN client
I went through
and then added Site-to-site section from

My approach is to have full access between all clients in both networks.
As fro now I have access from clients's LAN to servers one, and from server only to clients LAN. Trying to tune that. But this is not the most important thing.
I cannot see anything related to VPN in Servers's LUCI or via 'uci show openvpn' - only standard examples, no my own VPN network. However it works!
I understand that it is configured via external script, but - is there a way to transfrom the setup to native one?