While the custom keyboard community does tend to get in to pointlessly overcomplicated cables similarly to audiophiles, unlike the audiophile crowd no one really tries to claim they actually do anything beyond looking good.
IMO the keyboard community does a pretty decent job separating the subjective from the objective. People will go deep in to rabbit holes about their preferred feel and sound, but they acknowledge that once you've gone past the entry level basically everything other than ergonomics is pure personal preference and even ergonomics has a lot of personal aspects to it based on your own physical needs, setup, and use case.
You won't find anyone trying to claim that their magical USB cable makes the bits go faster, unlike the audiophile world where $500 ethernet cables are a thing.
As for choosing the right one, the best is to try them out at the store if you can. Find the one that looks and feels the best, buy it, plug it in, done, drop-in replacement. You can't really go wrong, these are just keyboards.
I'd say the only feature you may look for that is not obvious is NKRO (N-key rollover), or the ability to press any number of keys at the same time. If you are paying $100 or more for a keyboard, it is something you want. Most keyboards in this price range have it. 6KRO means you can press any 6 keys at the same time, it is not quite NKRO, but unless you have special needs, it is just as good, 2KRO (2 keys) is the one to avoid. It is sometimes called "anti ghosting" but some manufacturers cheat, so, not a reliable indication.
There are other features like hardware remapping, RGB lighting,... but if you need these, you will know beforehand.
Small caveat though. Many mechanical keyboards, especially in big box stores have clicky switches, clicky switches may be perfectly fine for you, but chances are that people next to you won't like them as much. Please be considerate of your surroundings when using a loud keyboard (are we back into audiophile territory ;))
I never considered a mechanical keyboard before seeing comments fawning over them. I was already a fast typist and had some strong preferences about keyboard layouts, bindings, ergonomics etc. There was never a huge community around this so I was quite intrigued when I discovered these people who cared so much about their keyboards. Somehow all these years I must have missed out on mechanical keyboards. I tried a few and even the "light" switches are SOOO much more tedious to type on than (decent) modern laptop-style keyboards. Searched around and most in that community seem to take the position that indeed they don't help with typing speeds, or are in fact slower to type on, but they're more "comfortable" (which doesn't make much sense to me). I want a keyboard that's good for typing/using. I don't care if it's "mechanical". Sure, people have their preferences, but this mantra of "mechanical" somehow being inherently advantageous all else be damned originated with that community. When I see people pushing mechanical keyboards I always suspect they've been heavily influenced by them.
I had to replace a failed keyboard last year and went looking for advice - when I last did it it was basically a question of "do you want clicky or not switches? Das is a pretty reliable brand but Razer has some stuff with RGB if you like that"
Now it's all "Oh don't buy an off-the-shelf one, wait for this dude's next massdrop order or buy a kit and put it together yourself"
And I just don't have time for that. This is one area where I'm pretty happy just looking for a recommendation for something I can just buy and use.
Go for Cherry MX Switches. Want clicky (and loud) take blue. Want tactile go brown. Want no bump at all when typing go red.
I would find a cheap second hand board and see if you can appreciate the experience. It probably will not have lubed switches or may have a scratchy bump or hollow sound or whatever the hobbyist tell themselves to justify a new board. You probably will already be amazed by the quality improvement and won't care.
No, black. Red has an extra high activation point and much lighter springs (marketed to gamers for quicker reactions) that often misfires when the user rests his hand on the board and doesn't take special care not to press anything. Black is the standard office class linear one of the bunch with the weight matching brown and blue.
There’s plenty of options now particularly at the lower end of the market the issue here is QC though. Two people can buy the same board but the fit and finish might differ wildly.
If you immediately want to spend hundreds on a custom setup and are paying someone you've never met to do it for you, before receiving any kind of product, that's where it can get dicey.
Computer Keyboards… not so much :(