1) The docking station is horribly buggy. If I unplug it to take my laptop somewhere and then plug it back in, I have to do a full reboot or none of the USB peripherals on the docking station get power. Monitors, power, ethernet all still work through the docking station after being plugged back in. Dell support took 4hrs of my time installing/uninstalling drivers and firmware updates before finally giving up and sending me a new one. Which suffers the exact same issue. So I can buy a different brand of docking station, not take my laptop anywhere, or constantly reboot my machine.
2) Rebooting takes forever then fails. Every single time. After 8-10 minutes of sitting on the blue "Rebooting" screen it finally crashes and tells me something went wrong while rebooting. Every single time.
3) Sleep still doesn't work about a third of the time. If I put my machine to sleep through the Windows start menu and wait for all the various indicators to power off before closing the lid, there's a good chance that when I boot up tomorrow, the battery has fully drained and the machine has to boot back with all my applications closed down and context lost.
It makes me miss my Thinkpad.
To answer your question, I don't switch OS because the machine belongs to my employer and they set the rules. They say everyone runs Windows so I run Windows. It's actually a very usable OS.
You also seem to have missed the part where I spent 4 hours on the phone with Dell support already. Why would you expect that will be more successful with a different OS?
Ultimately, I gave up and bought an intel nuc with an M2 SSD and plenty of ram. It just works.
I've (sadly) heard similar reports for Linux on Thinkpads (eg https://www.reddit.com/r/thinkpad/comments/9fos6i/x1_extreme... - and plenty of other reports on other models).
Ubuntu 18.04 has been rock solid for me on the XPS, and it has been getting BIOS updates (and Linux has been getting device driver updates if I want to reinstall).
Linux worked perfectly on the Toshiba I had for the previous 4 years (I didn't buy it with Linux in mind, it just worked).
In my experience, Windows laptops often get "driver rot" over time (amongst other issues). As a developer I can usually fix the Windows issues, but it certainly is not a painless task.
Dell's XPS Windows drivers were particularly bad considering the sticker price - Windows blue-screened two clicks into the install after opening the box - and I had some other blue-screen problems that took me a while to resolve when I first got the laptop. I haven't booted into Windows after installing Ubuntu, and Ubuntu has given me far less trouble than Windows (on this machine).
Run Manjaro with gnome-shell (actually gnome-shell-performance until 3.32 is released). Its lightening quick, reasonably stable, good battery life.
I also tried KDE, which works quite well, but the battery life was quite poor and I find the general KDE experience abrupt.
Now my 2017 mbp just gathers dust, never going back.