There are definitely still fully remote roles out there, the issue is that as they get more scarce the demand for them will only increase. From what I've been seeing personally, it seems that situations like yours where you're at a startup that just doesn't have an office at all are probably the best option for truly remote work for the time being. There are companies like Spotify, Airbnb, Coinbase, and some other big names that are remote-first where you might be able to make your desired >30% increase, but it'd likely be a bit difficult to get those roles. IMO, it sounds like you're in a position where you're pretty comfortable at your role so it could be a good idea to just brush up your resume and LC skills a little and start applying to places just to see what's out there.

Yeah look for remote-first companies and apply there first, but if no luck, then I say don't sacrifice WFH if you value it that much. Try to quantify how much money you'd have to be offered to be okay with going in office and, if you don't get that, then don't go. For me, I can live NICELY off $180k and $220k is a big bump, but not so big that I'd sacrifice WFH at all.