The average new Manjaro user who has been registered on the forum only a brief amount of time does not have 10 years of Linux experience. It’s great you do, but most new users on the forum have little (or no) Linux experience and most are fresh off the Windows boat.
For those users my advice is perfectly applicable, as they are not going to start bisecting kernels. You may be a more advanced user, but that was not immediately apparent from your earlier posts. Your initial post did not make it appear that that you were an experienced user as you stated you just just installed Manjaro and provided zero system information. A user that is more advanced generally posts their specs or logs right off the hop, (not after a dozen posts in the thread).
I use kernel 4.14 as my daily driver and there is absolutely nothing wrong with that, as it is an LTS kernel that is supported for quite some time yet. If 4.14 runs fine on your system there is little need for you to be on the latest kernel. I could see this being a major issue if the only kernel that your computer ran on was an end of life kernel such as 4.18. Then debugging your computers problem with the newest kernels would be of major importance.
Generally major incompatibilities with mainstream hardware is resolved fairly quickly when there is a kernel breakage. For example I use a Realtek wifi adapter that broke on kernel 4.15 for a month or so. It is currently broken again on kernel 4.20. Neither breakage was a major concern, because I expected it to be rectified before too long. The important thing is to have an LTS kernel that your system runs well on (and you do).
If you are such an experienced Linux user start showing it. Put on your big boy boots and start posting some logs, (as requested) that might actually be useful. Instead of putting down forum helpers that respond to your thread with nothing but good intentions, start helping yourself.
Unless my response is off topic you really have no business telling me not to respond to your thread, and putting down my advice. If you looked at my number of solves on the forum in the last year you’d probably realize that my advice is usually pretty good. IMO your response to me was a very poor way to introduce yourself as a new member who is expecting help on the forum.
Good luck getting your issue resolved.