GSC doesn't have Natures/Abilities/EVs.
You can just catch what you like and immediately jump into the fun gameplay (combat and levelling up).
All you have to worry about is movepool.

RSE revamped the inner mechanics in an attempt to make each pokemon more unique, that was the idea behind it. But ask yourself, who actually gives a fuck about the "individuality" aspect of a pokemon? Even worse, since everyone and their grandma knows how these mechanics work now, it has triggered the collective OCD of the pokemon fandom to get the 'Right' nature & ability. People want the best possible values for their bros. This has degraded the fun and enjoyment of pokemon games. No one enjoys the endless grind for 'correct' Natures and Abilities. Everyone knows it's a tedious chore.

Abilities for a lot of pokemon is a 50% chance they have the "wrong one". Natures on wild pokemon are fucking annoying, especially in the early game. That Weedle you can 1HKO with Tackle in Viridian Forest no problem in RBY? Sorry, youre poisoned now, you need to backtrack to Viridian. In FRLG, you end up getting pushed into using special sweepers moreso than physical just to avoid the fucking tedium of condition-on-contact abilities.

Natures basically introduces something like a better than 50% chance that the pokemon you catch is going to have a -10% to one of the stats you want. It's particularly grating when it's -speed, and you'll have no idea since the games don't spell out what Natures do what - so you might get a false impression a pokemon is slow and useless, rather than a good pokemon saddled with a shit Nature.

Gen 3+ IVs are literally twice as bad as the old DV system.
EVs are the most autistic way to replace the stat EXP system possible.

>But you don't HAVE to care, you can beat the game with a Sunkern!
That's not the point. Once you LEARN these hidden mechanics, you can't escape that knowledge.
Modest Tauros? Trash. Adamant Abra? Crippled. No one wants to use subpar pokemon.