Re: Curiously, I watched a video yesterday
Oh boy - yes, both keyswitches and keycaps are complete rabbitholes, and there are so many potential combinations that someone selling a product can't possibly hope to cover them all.
Do you want your switches to click when you press them? Do you want smooth linear travel or a tactile bump? How heavy? Do you want heavier springs on the keys that fall under your index fingers?
What colourway do you want for the keycaps? Do you want them made of ABS plastic (cheaper, higher-pitched sound, less durable) or PBT (more expensive, more durable, usually "better" sounding.) Do you want cutesy multicoloured keycaps with Japanese characters or vintage Wyse terminal keycaps (yes, they'll likely fit just fine.)
And that's before you've entered the realms of stabilisers and lubrication.
But with all these options, the one that's hardest to find is the one that actually matters to me: keycaps in ISO / UK layout ("£" on shift-3, backslash cut out of left shift, '#" cut out of an L-shaped enter key - ANSI (with thin horizontal enter key) seems to be all that's served by 98% of the market.
Chyrosran22's videos on YouTube are endlessly entertaining (but NSFW) if you want to see reviews of some modern but mostly vintage keyboards, and a viscious (but well-deserved) skewering of certain fashion trends.
(Typing this on an early 90's IBM Model M.)