I think I am one of the few who actually liked the ATMA quest.
I met some new friends, visited areas I had completely missed before, and did some FATEs that I didn't even know existed.
It never felt "grindy" to me. Maybe that's just from playing other FFs idk.
In total it probably took me about two weeks with running a few fates a night. If I was finding my luck was sort of low, I'd quit them and come back later.
My one complaint would be farming Lower La Noscea...ugh so large.
Any others who enjoyed it?