While ubunttu and many other distros have come a long way, there are still many limitations that can play a large role in determining if someone will have a good or bad experience.
One issue with linux distros in general that has not change much is that they were well suited for both novice and extremely skilled users with more in the way of frustration for those in between. My reason for this is that there are things which can quickly put a user through an unforgiving CLI tar.gz gauntlet, with often guides that are hit or miss.
For example, if you have a peripheral or other device that does not work automatically with your distro, and the software center does not have any applications that solve the issue, then you are stuck looking around and hoping that someone did a .deb package that can automate handling dependencies and making this work. But if nothing is found, then you are stuck searching various forums to see if anyone found a solution. The issue is once you reach that point, often if you find something, it will numerous threads with people asking for help and no replies, and then finally one where someone goes the distance and points the user to a package that can meet the user's needs, and then proceed to list off a 20+ step process to install the random tar.gz package, and surprisingly enough, it e ends p working for the OP of the thread, but the user who stumbled across the thread would likely not have the same luck, the instructions were writted for Ubuntu 20.04 and the new user looking for help has Ubuntu 24.04 and while copying and pasting the commands seemed to be working, things started to fail 17 steps in and now th euser has random files spewed all over the place without muck knowledge on how to clean up the mess.
While long winded, that represents a fairly common scenario with Linux distros in general. There will often be an increadibly easy to use waled garden experience, but the moment you need to step outside of that walled garden, then it is often CLI hell.
Beyond that, there are often many additional features that many system components will have that ubuntu linux does not properly support. For example, suppose you have a Creative Soundblaster AE5 Plus, a Logitech gaming keyboard, Logitech gaming mouse, and a Blue microphone yeti, and you want to use the macro keys on the keyboard, as well as the macro keys on your mouse, in addition to the noise cancellation and other audio processing functions on the mic, as well some of the DSP functions of the sound card (e.g., some of the additional room correction and calibration features). You would find that there is nothing in the ubuntu walled gardento meet your needs.
Or even worse, suppoe you want to run a linux distro on your laptop, and you want the DSP features for the laptop speakers. Most laptops improve the perceieved sound quality and bass extension of their speakers using a wide range of DSP tricks, including reproducing harmonics from certain dounds that fall below the frequency response range of the speakers, which causes you to percieve more bass than is really there. Often the basuc sound support in ubuntu will result in none of those special DSP features being used, thus resulting in the speakers sounding more tinny than they should.