So shared this in another post as well, but for anyone else having this problem of difficulty connecting at a Hilton with the Captive Portal not appearing, this is what fixed it for me:

Go to the VPN Dashboard → VPN Client → Global Options, and uncheck “Block Non-VPN Traffic”. I also had to set my WireGuard to disabled to get the captive portal to come up. You can turn WireGuard back on once you’re connected.