I'm having good fun in Eureka orthos. I've just been doing it solo the whole time and I've only managed to get to floor 31 buts it's hell fun. More than potd where mob damage is very high.
Love challenges which are solo as well as group just like variant dungeons which are soloable as well as group mode.
Even though the mechanics are very punishing it's very satisfying to clear them and rewards are cosmetic.
This is what I had hoped tourghast would have been.
Difficulty balance is so right.
I can play many classes as solo.
It is a bit time consuming as it takes 40-45 mins to complete 10 floors and it might take me months to do this purely solo(since I can give Max 2hrs a day) but this is my "ultimate raid".