If Netscape had a large paid install base and still failed because a free browser became ubiquitous, what makes you think doing that now when the free browsers are already ubiquitous would work? Especially when it also has to compete with what is essentially already what you’re describing, Librewolf (or just Firefox + Arkenfox).

I don’t have anything publically accesible on my network (other than wireguard), but if I did I’d just put whatever it was on its own VLAN, run a wireguard server on it, and use a VPS as a reverse proxy that connects to it.

I only use unprivileged LXCs and everything I host on my network runs in its own LXC, so I’m not really worried about someone getting access to the host from there.