Everyone else has explained the RP versus raider thing so I'll just focus on the Ultimate cancellation.

Ultimate is special raiding content past Savage. It requires very precise balancing and thus a significant amount of development work.

Yoshi-P announced recently that the Ultimate that was scheduled for 5.5 was being delayed to 6.1. He explained that the decision was between getting the Ultimate out or delaying the Endwalker expansion further. Endwalker is already late for an expansion since they usually come out in the summer. But their development cycle is about 3 months behind due to COVID.

It was nothing to do with any other specific content in the game. But some just latched on to the idea that Ultimate was cancelled and made up their own reasons. The reason is because they chose getting Endwalker out which everyone, even Ultimate players, can enjoy versus getting the Ultimate out for the 1% of players who would experience it.