The gradient of difficulty in this game is so steep even a mountain goat will struggle to climb it. A big reason why so many players of all skill levels are unsatisfied is because there isn't a good gradient that can keep these players hooked and challenged without being too hard.
The jump from normal duties to Extreme is fairly significant. Even in a decent static, you'd still need 1 to 2 hours of wiping to Endsinger to clear it. It'll be far harder in a PUG. This is massive step up from normal duties which pretty much almost never wipes.
The jump from Savage to Ultimate this tier is also very significant. You already have players complaining that this Ultimate was unreasonably difficult. Those people need to shut up but there is some truth behind that complaint: Savage has become so easy for seasoned veterans that it becomes mindnumbingly boring for them after the clear. In my honest opinion P4S does not adequately prepare anyone for an Ultimate encounter. This particular Ultimate is only adequately prepared for by actually doing on-patch Ultimates, the most recent of which took place a whole 2.5 years ago. This is why so many players who only did Savage and SB Ultimates in ShB (which is seriously only as hard as a Savage level difficulty fight, and this isn't just a meme) are struggling with DSR and even breaking up over it.
There needs to be far, far more content of all kinds of difficulty levels. I would propose an Extreme difficulty alliance raid where players will wipe two or three times each encounter, but give players individual extreme/savage-difficulty mechanics that, when failed, only result in their own deaths. This would be pretty similar to Baldesion Arsenal, where the mechanics may be challenging for newer players but ultimately don't impact the group that much, resulting in a low-stress environment for people to get used to harder mechanics and reacting to those mechanics faster. To save developer time they can start with making the Extreme difficulty raid then shave off mechanics and DPS checks to make the normal difficulty version.
There also needs to be something between Savage and Ultimate, both to satisfy veterans who are only challenged by Ultimate these days, and to help players bridge the gap between Savage and Ultimate. Once again, they can simply make a harder variation of the Savage fight and tune it to the max ilvl for that patch. In many of the Savage fights, they are already starting with difficult mechanics and trimming off mechanics that are too difficult. They simply need to preserve the pre-nerf version and make it Savage+.
This game absolutely does not help players get better and it is a serious shortfall that has been getting worse and worse since Heavensward.
The Creator difficulty gradient was in my opinion the best difficulty gradient the game has been at in its history. Normal content has a significant chance of wiping (Mhach and Dun Scaith in Heavensward) which serve as training for the player to get better. Sophia and Zurvan were no pushovers, but their mechanics are simple enough that I felt that they were only a few steps up above an alliance raid. Finally, A9S-A12S were much simpler than Gordias and Midas, which allow for people who have tackled an extreme trial to go on to Savage pretty comfortably.