I actually enjoyed my time instructing in a sim, but I did find that my raw skills deteriorated when not flying regularly.

Years ago I entertained a FSI position, because it offered regular hours close to home, benefits, etc. In the interview, which went very well, the retiree-interview panel noted "You'll be operating a simulator, rather than flying, and we're looking for long term staff. Are you prepared to end your flying career today?"

Great position, but no, I wasn't. I spent a lifetime building and maintaining that career, form the time I was in my early teens. I wasn't prepared to end it that day, or even put it on hold for a few. years. Like I said, I have enjoyed operating a sim and teaching in one, and I'd do it again, but I'd rather be in an actual cockpit. You may find that it works for you; there's only one way to find out.