Most wifi cards on Laptops now are either Intel or Killer. So most distros will ship with these common ones. They also usually ship with universal drivers for things like trackpads and monitors so that at least everything "works" out of the box on a fresh install. However you still are best hunting down specific drivers for your equipment to get the best experience or performance.
My personal experience is that if you use a Dell or Lenovo laptop, that you won't need to worry about compatibility. These two companies in particular seem to have the best linux support so their equipment generally just works. I have found HP to "mostly" work. Good luck with Asus or Gigabyte. I wouldn't even try a lesser brand than those.
Battery life on Linux is a mixed bag. There are tools you can install that can give you incredible control over your battery and drag a battery's life out much longer than you would get from the same laptop on Windows. But you will need to constantly manage it and be aware of it. For example I need to go into the terminal and manually change a profile every time I connect and disconnect from the charger. As opposed to Mac and Windows that mostly manage themselves to get the best performance/battery life ratio. I found that if you don't do anything with Linux and just run it on battery that you will get substantially lower battery life than the same device would give you on Windows.
Let's be real you won't buy the cheapest Fujitsu or whatever anyway. You are going to get a proper ThinkPad or something and than Linux is the faster and better working system either way.
That was 5 years ago and I never looked back. I think that adapter is the secret key. Once you have that it doesn't make sense why you wouldn't use KDE Plasma.
I literally only know LS MKDIR and then conda commands. I don't know what any folder does outside of /home. I don't care about these things. Everything has always just worked and if something breaks I can reinstall in about 10 minutes.
The experience people describe on here is what I remember in 1999 when I spent a week trying to get my soundcard to work and gave up.
Asus EEE 1005HA
Asus U36G
HP EliteBook 8470p
HP ProBook 430 G6
ThinkPad x220
Acer that I don't remember by model number (I have installed it for others)
Yes, the wifi issue is solved since like 2013. You usually only need to install firmware, which is a standard package from your distribution's repository (some user-friendly distribution even do this for you).
The second thing (and which you mention) is the laptop install situation, I was never sure if running Linux on whatever laptop would work, and if yes if it would work 100%, meaning no wifi/sound/battery drain issues. That was one of the main reasons that has kept me away from Linux since then. Granted, if Apple goes on its current way of trying to restrict access to its machines I may make the switch back sometime in the near future.