Hello, to not assume things and post messy descriptions, I start with a scheme:
What is working now:
1) Connection between Location 1 and Location 2 LANs. I can access all LAN devices of both Location 1/2 networks from either Location 1 or 2.
2) I can access Location 1 LAN from a Mobile Device that connects to Location 1.
What is not working and I am trying to acheive:
I would need to access also Location 2 LAN devices from Mobile Device that connects to Location 1 router. This means connecting L2TP/IPSEC and Wireguard somehow in Location 1. That is something I haven't found out yet how to.
The image of Location 1 /IP/Routes when Wireguard is up and also one L2TP/IPSEC device is connected: