The overhead of a VPN will reduce the MTU (ie the traffic inside the VPN needs the headers from the VPN itself).
So if the first VPN reduces your MTU from 1500 to lets say 1420, but your next VPN is trying to send 1500 byte packets it won’t work.
On another note, always provide feedback to the hotel about the lack of IPv6, the complaints add up and eventually they will take some action.
Yeah could be, having a vpn inside a vpn can sometimes be a bit of a pain. Maybe try a openvpn connection to hide.me and wirerguard home? I haven’t tried that myself but you’d think it would work.
then I activated my Wireguard connection
Why? I assume you want to access stuff on your LAN, which has IPv6?
… or is this to access other stuff on Internet from you wireguard at home?
Let’s throw IPv6 on Noah’s Ark and pretend IPv4 didn’t exist if the world goes to sh1t 
Love the T