nextDNS not playing nice with ProtonVPN
I have nextDNS working on my Mac fine. But when I create a ProtonVPN tunnel to browse, the browser is unable to open any site. I have to disable nextDNS first.
Haven't tried this on ios but presume it's the same.
I don't know how macOS works, but maybe it's like on iOS, you can't have both VPN profiles active at the same time.
For example, I use the Apple Configuration Profile (https://apple.nextdns.io/) on my iPhone, and it works well, but when I connect to a VPN server the DNS queries are forwarded to the VPN server and not NextDNS.
Basically my iPhone used NextDNS to resolve my VPN server hostname to connect.
I don't think you can change ProtonVPN DNS settings with your own unluckily.
You can still use NextDNS via DNS over HTTPS on Firefox and most Chromium based browsers like Brave etc (I don't know if Safari does have it.)
Hope I helped someway
Came across this workaround on Reddit. Works for me, but involves buying another VPN app for $10ish dollars that lets you use your ProtonVPN profile while also specifying custom DNS settings.
I'd imagine if you use the OpenVPN client app instead of the ProtonVPN app you could import your ProtonVPN profile and override the DNS settings as well, if you wanna save $10 or don't want to trust another app.