1 Adguard home works via vpn, although it should not, because the IP address of dns servers is not included in the list for tunneling
3 Maybe this option (Allow Access WAN - what does this option do?) should always be enabled (I didn’t find a description), but if you don’t turn it on, then (when you turn on the vpn) the Internet starts to slow down (in general, the download speed doesn’t drop, but there may be a big ping or something else)