That was certainly not the case ~2 years ago, the last time I installed linux on a laptop.
It also doesn't appear to be the case even now. I searched for laptops available in my country that fit my budget and for each laptop searched "<laptop name> linux reddit" on google and filtered for results <1 year old. Each laptop's reports included some or other bug.
The laptop with the best reported linux support seemed to be Thinkpad P14s but even there users reported tweaking some config to get fans to run silently and to make the speakers sound acceptable.
Not all distros that exist in the current year are "modern". Mint for example, still ships with X11 and old forks of Gnome. Lots of people are running Arch with weird components that don't work well for whatever reason. And so on...
Modern means systemd, pipewire, Wayland, Gnome, an up to date kernel, etc... So the current Ubuntu and Fedora releases.
I've had 100% working laptops for 15 years now. Because I always run the newest Ubuntu.
I run Ubuntu and suspend is pretty much a nightmare to the point I just gave up pretending it exists. These are Dell computers sold with supposed Ubuntu support. Close the lid and put it in a backpack is inevitably an invitation for a hot laptop or empty battery when you pull it out a few hours later (for the record: Windows isn't any better at this in my experience so WSL never solved that problem either).
Previous laptops (all ThinkPads) used to be able to get everything all to work (debian) but it did take effort and finding the correct resources. Unfortunately all the old documentation about this stuff is pre-systemd and UFI and it's not exactly straightforward anymore.
Google "Dell suspend issues". It's just their computers, it doesn't work any better on Windows. My wife has had 2 Dell laptops now, neither suspended properly ever (and she only runs Windows). According to the internet, this is a Dell problem. One of her laptops also had the Wifi card break within 4 hours of use, brand new. But she likes the "design" and is stubborn.
Google harder. It's a general Windows problem. Microsoft can't even get it to work on their own Surface devices. Show me a Windows laptop that suspends properly and I'll show you a liar.
Well there you go. Meanwhile Linux suspend does work more often than not in my experience. I've had a ThinkPad, Acer and MSI laptop with working suspend on Linux.
Other than an up to date kernel, your list of what "modern" means is entirely wrong. The rest of the entries are polarizing freedesktop-isms. There's nothing out of date about, e.g., KDE Plasma.
I read all the links, most of the problems weren't bugs (Fan runs loud? Fans run under Windows as well... Only modern suspend? Literally created for Windows...). From all those links the only thing that was a bug was an issue with a kernel regression and 4/5 distros he listed weren't one I listed.
Maybe I was too positive on Fedora (I was going by it's reputation, I use Ubuntu for work). Ubuntu is solid.
Link 1: screen only updating every 2 seconds, visual glitches.
Link 2: brightness reset to full on screen unlock, fans turning on when charging.
Link 3: bluetooth troubles, speakers cant be muted if headphone jack is on mute.
Link 4: audio quality and low volume, wifi not coming back after sleeping.
Link 5: fans being too loud, poor sound quality.
Either your Stockholm syndrome is affecting your reading comprehension or you just take bugs like these as part of the normal "working perfectly" linux experience.
Nothing works out of the box with Linux. They may "seem" to work out of the box but you realize how many little tweaks go into making a laptop/consumer device work fully when you work as an embedded dev. It is quite difficult to get to the same power consumption levels and same exact hardware / software driver capabilities under Linux. There are simply no APIs for many things. So the entire driver has to live in userspace using some ioctls to write random stuff to memory or it cannot exist. There are also algorithms that the hardware manufacturer wants to keep closed.
Note that NVIDIA drivers didn't get better since they are more open source now. They are not. GPUs are now entire independent computers with their own little operating system. Some significant parts of the driver now runs under that computer.
Yes the manufacturers may allocate some people to deal with it and the corrosiveness of the kernel community. But why? Intel and AMD uses that as a marketing and sales stragtegy. If the hardware manufacturer is the best one there is, where is the profit for supporting Linux? Even Thinkpads don't have 100% support of all the little sensors and PMICs.
HiDPI issue hasn't been solved yet completely. Bluetooth is still quite unreliable. MIPI support should be the best due to the number of devices, until you realize everybody did their own shitty external driver and there are no common good drivers for MIPI cameras so your webcam doesn't work. USB stack is still dodgy. Microsoft in 90s had a cart of random hardware populating the USB tree completely and they just fucked with the NT kernel plugging and unplugging until it didn't break anymore for love's sake. Who did that level of testing with Linux?
Then you cannot claim that Linux works out of the box. It doesn't if you need to select hardware for it. However, I already know that since I actually used Linux for 15 years. Both on the consumer side as a normal user for 15 years and now I am actually an embedded Linux developer. The underlying architecture of GNU/Linux distros is heavily server biased which often is the polar opposite of a consumer system.
Except for Apple (and maybe Framework), all laptops are designed by contract original design manufacturers (ODMs) Taiwan, Korea and China. Your usual Linux laptop OEMs like System76 and Tuxedo just buy better combinations of the whitelabel stuff. They are inferior to actual big OEMs designs which contain more sophisticated sensors and power management and extra UEFI features. This includes business laptops Dell Latitudes, HP Elitebooks and Lenovo Thinkpads. None of those manufacturers actually do Linux-based driver development. All the device development, manufacturing and testing is done under Windows and only for Windows. The laptops are booted with Windows to do functional tests at factory not Linux.
Linux is an afterthought for all OEMs. After Windows parts are released and tested, the kernel changes to Linux is added. They are rudimentary support which doesn't include 100% of the featureset. Many drivers today have quite proprietary user-space side. You'll get none of that from any laptop manufacturer. You may say you don't care about those and you're okay with 10 - 20% power loss. That's not the definition of out-of-the box for me.
