tldr:
For Linux adoption it would be better for devs to focus on 2 ("main") distros which are very similar to Windows and macOS and then 2-3 further ("big") distros which give a bit more room to experiment. All the other distros create confusion and analysis-paralysis for the user who wants to switch or wants to help others to do the switch.

--- (sorry for the long paragraph, i ranted and brain dumped the idea)

I see a problem: Even "stable" distros like Debian and big and "fully developed" DEs like KDE or GNOME arent ready for the majority of the users switching from windows.
Missing software compatibility and the need to fall back on the commandline are just some of the problems.
The biggest one is the confusion for the average user: They google "install Linux" and then need to do research for at least 30minutes, figuring out which of the popular distros is the right one for them. If decided, then (depending on the distro) they then have to choose the DE.

Its a sinilar problem to the adoption of the Fediverse: You are expected to decide what instance you want to be part of.
This makes it also very hard for a linux enthusiasts to convince/help install a distro for a family member, as you dont know their preferenced or how they use their Win/Mac machine. So either you as an expert have to observe and then do research on what distro+DE fits the usecase or the enduser themselves need to distro-hop, which is obviously not happening.

Now you are thinking: But just install Linux Mint and they probably do most of the things in their Browser anyways.

But in my experience the switch of potentially the browser, the mail-client and ontop of that the OS is a pretty tall ask for an average end user. So the whole switching thing becomes a multi year operation where they first switch the software they use to FOSS one. Which is a tall order and it makes it even harder to explain and convince someone.
Heck, it already takes multiple days to get my grandma up to speed after the change Win10 -> Win11, because some buttons moved and the context menue looks different.

Now my utopian idea:
If there were only a handful of popular distros+DEs, one could map them on a 2D-plane or even on a spectrum of "fixed, you have to adapt" to "flexible, you have to adjust the settings".
Mac users could switch to a distro which is quite fixed (comparable to macOS). This fixed distro should out of the box be close to the mac experience.
With windows the same.

Very very rough prototype of the spectrum to visualize my idea. I dont know enough about it but tried anyways:

flexible

Windows 10

MacOS

fixed

If then most of Linux Devs (from Kernel to distro to UI to software) mostly focus on the 4-5 main distros, then they would get more stable and they could be made to behave closer to their proprietary counterparts.

This then could make the switch from Mac/Win so much more easy because:

1. The distro is closer to the old proprietary OS. So the enduser just has to learn other "new" software, the OS doesnt demand a learning curve but just replicates the Win/Mac experience.
2. The decision which distro to use is easier, as there are the main ones which are easy to choose because they are distinct from one another.

Disclaimer: No, i am no expert, I probably dont know enough of the technical side, I just wanted to share the enduser experience.
Obviously there will always be countless distros by enthusiasts who tinker with their dozends of dev-friends for their personal-perfect distro. There will always be the people who deliberately do some frankensteined distro, and I am not here to forbid any of this.
The confusing diversity of all the options is just not helping the wider public.