Create your WireGuard VPN users on your Main site

Create your IPsec Site-to-Site VPN tunnels between Main and Other sites

Edit your WireGuard VPN user configs and add the remote networks to the AllowedIPs like this:

AllowedIPs = 192.168.3.1/32, 192.168.3.3/32, 0.0.0.0/0, 10.30.10.0/24, 192.168.1.0/24

Edit your IPsec Site-to-Site VPN tunnels for Other sites only, and add the WireGuard VPN network as a Remote Network subnet