I was about to write more but I don't think it really needs an essay after yours. I'm sorry to hear this is what the new duties are causing to you. I can actually relate, even though 1) I am not disabled by any means, and 2) I am not aging (yet) by any means as far as I can tell. When Yoshida said they'd try to make duties less of a snoozefest when specifically talking about casual content like dungeons, I was happy to hear it, but also a little worried in what form exactly it would take.

In fine it is exactly as you said, they doubled down on pace and mechanical execution of DDR mechanics. It is especially noticeable in the new dungeons where mechanics are chained in a way faster succession to challenge players on timers, while relying more and more on fast visual puzzles and feedback to gather from various parts of the arena. In raids as well, more and more relies on the latter, and they have literally sanded down all the battle system and jobs to make room for it. And while I am in no way handicapped, I can definitely feel the push in that direction, and I don't like it either. Not out of sheer physical limits, but out of that's not what I started playing the game for. My own performance has also dipped in savage content, and while this has been ironically the easiest savage tier for a long while, it is also the tier that has had the biggest amount of mechanics that I am properly unable to process well on my own, just above Anabaseios and alongside with Criterions.