This is a real dumpster fire. It isn't even the length of the grind, because it's a relic and those are always grindy and we don't have much information on bad the grind is at higher levels. For all anyone knows the total amount of time might work out similarly to atma.
It's just insanely boring and I cannot believe anyone greenlit this in 2018. This is EQ/FF11 tier tedious and only a tiny portion of players actually want that content, even if all of them won't stop posting about it here. Here is my pro-tip development team; the time where it's cool to ask players to just grind on trash mobs for hours on end has passed, and despite what you may think from the 2.0 days, people don't actually like fates either. Please stop trying to force this on us.