Hard disagree from me. I've loved the dungeons, trials and raids so far this expansion. In fact, this is the first time since Stormblood I felt inspired to actualy pursue doing an EX trial and got my first Valigarmanda kills in last night and it was great.
While the msq was a mixed bag for me personally, one I overall enjoyed in the moment but have issues with looking back on it, the pve content has been really good. The dungeons are all fun and engaging. (Even if the first dungeon ends up feeling kind of pointless story wise, it's still a fun romp.) Really the only boss fight I take issue with in DT so far is the first boss of Deadwalk, and that's only because latency can make dodging the enemies on that one frustrating and wonky rather than having an issue with the fight in theory.
For the first boss of the msq 100 dungeon, just keep an eye on the shapes as they appear and don't worry about doing damage if you need to and priorize moving into position for each one. It's a tight check but doable unless you have a lot of lag, which will get you killed in just about any fight anyway.
Any comparison to Dark Souls/Elden Ring is overblown. This isn't anywhere near that level, even accounting for how Dark Souls and similar games tend to have a reputation for being harder than they actually are. Not everything mildly challenging is 'dark souls.'