I'm all for your move Geographer! I get that it's hard to take a pay cut, of course. Suddenly you're giving away the same amount of time and skills for less money. Ouch. It also means that you aren't able to invest as much towards FIRE, and it delays progress. Ouch. Bbbbbuuuuuuutttt, I always try to remember that the point of all of this is liking your days. So if your path to FIRE takes a bit longer but you actively enjoy the journey, instead of suffering through it, then I'd say you're absolutely making the right choice. Try to think of it this way. This isn't an un-Mustachian choice, this is a choice that you can make because of Mustachianism.
I may be in a bit of a similar position (Expect to know more on Wednesday). I've been at my current job for 3.5 years, and I've been bored out of my fucking mind for 3.25 of them. This is partly because of the demands of the job (It's simply the easiest job I've ever had) and partly because of my personality type (I need a TON of novelty, and new experiences to stay interested, so jobs typically keep me interested/challenged for a few months before I start wondering how long I have to stay there to avoid thinking about how bad leaving would look on my resume). I've been considering my options for a year, and just had a job interview (Hilariously enough, at an airport as we were both waiting for flights back after a conference) with a job that I expect to be able to do ~75% remotely (That's still a discussion point). I suspect it'll pay more, but it might not. I expect I'll take it even if it doesn't - A new challenge, new people, new stimulation, and REMOTE WORK is worth a few thousand bucks a year to me.