Another approach to FIRE that I think is actually more fulfilling is to gradually reduce working hours until "retired".
For example, explore a position that lets you work 4 days a week and take Mondays or Fridays off. Later, switch to part time or contracting 6 months on 6 months off.
I don't personally think gap years will be very fulfilling unless it's something like a whole family 1 year vacation where you all go and live someplace.