Haukke HM is very speedrunnable and gives 50 myth. Sirius and Copperbell are really not worth it in the same way, though fun dungeons in their own rights. Already done Haukke in 13 minutes, and that wasn't with 100% optimal pulls and timings in general, yet. With the cliché PLD/WHM/BRD/BLM comp you can just burn through it like it was 2.0 WP all again. The first section before the first boss kind of limits the pulls a bit due to the doors and the keys, with only a few NPCs in each room, but it gets better with the corridor sections after the first boss allowing for massive pulls.

Apart from that, the Duty Roulette and Coil are your friends. (Can't really comment on CT yet because I haven't done it yet, missing out on the FATEs, lol).