So, just wondering, how long sdo you think it should take?

Buff the drop rate? Some will still get it faster than others. To 5%?. Thats still 95% chance to not get one each fate, so you could still end up doing 100s with no return. 5% success rate does not guarantee that after 100, 5 of them would be successes.

Sell with seals? Still have to do FATES.

Dungeons? At least theirs variety with FATEs, and its open world.

I'll take FATEs over running the same limited dungeons over and over and over and over as have to for the books.