From the quality of pics on this forum and the comparison YouTube videos you can find, you can see for yourself the top reps these days are all very very good.
A bit of research and you can work out what factory the YouTubers are reviewing.
It's also plain from the available 3rd party GMT and Daytona bezels and crystals where the problems are on those models.
After that its just the n'th degree of finishing which you can get done for a few hundred $, shockingly a $500 Chinese watch isn't finished quite as well as a $40,000 Swiss one!
Added to that, often you've got a 2 week old watch that should have 10+ years of wear, servicing and cleaning.
I think people (especially new people) worry too much.
No one is going to question any modern top rep, what they might question is you.
I'm a 53y/o divorced IT guy with a near 6 figure salary, that I'd wear a Submariner is totally reasonable.
That I'd also have had in the past 18 months a GMT, a Daytona, a 5711, a Royal Oak, a Seamaster, a Black Bay and another 3 Submariners (I think that covers it) is perhaps a little less realistic.
If you really want to pass it if as gen in all situations, buy something you actually could afford if you tried.
Also, choose the rep with the care you would if you were spending gen money.
Most people with a gen watch have one or two and it's something they've really wanted for a long time, not a dozen of the things.