ARR fates are some of the fastest ones over other expansions. The way you're scaled the enemies are a joke and the way the zones are designed for running on the ground means flying trivializes the travel time. HW and beyond zones are far more massive.
Both are repetitive and monotonous and I've never really used either to level alt jobs that heavily. I am certainly not super casual and I got all 80's just doing leveling roulette + MSQ roulette each day. It took me maybe 6 months, and would have taken far less if I'd started this expansion with all 70's. But going into endwalker with all 80s will be nice.