Yet, nothing that you mentioned would help improve your team or truly make your Pokémon stronger when playing competitively. The reason this "worked" for Pokémon Legends: Arceus is because it is a single-player game for causal players that battle against NPCs, whom are much more likely to have Pokémon that are much weaker than your own without advanced AI.
Not everything is about competitive. My point is about game design, don't know why you take criticism over team building mechanics so personal and argue argue about any arguments against IVs/EVs because you're a pro who loves competitive, and those who criticize those aspects are apparently just lazy casuals who don't understand how things work.
This video explains it, and the comments show why a lot of players prefer it.
https://www.youtube.com/watch?v=t7f38FjtWc8
You say Legends Arceus has boring repetitive grind (which yeah, in some areas it has), yet you apparently love and justify the boring repetitive grind in the main games, because it's fine when it's all for the mighty competitive. So since PLA doesn't have competitive it makes sense that it's not worth your time. So apparently you do agree that grinding is bad, you just endure it when according to you it's for a good cause.
The entire point of competitive Pokémon is to determine not only which player has the best strategy in a battle to decide a winner, but also to determine which player is the best at training their Pokémon. The IV and EV system is a great thing for a number of reasons.
Having a 31 IV Gengar with 252 Sp. Attack and 252 Speed doesn't make anyone a better trainer, just someone who spent a lot of time grinding, which has nothing to do with skills. And it won't make that Gengar any special either because there will be tons of Gengars out there with identical or very similar stats. You can make your Pokémon or your team as a whole special in different ways, yet none of that has anything to do with IVs. Your point applies to EVs, because those do require some thinking and strategy and allow for different builds, but not to IVs.
No matter how much you try to sugarcoat it, you do selective breeding and forced RNG manipulation to obtain Pokémon with perfect IVs, which literally goes against the purpose of IVs you've mentioned about reflecting that same species can have somewhat different stats, and perfection (as in nature) doesn't exist.
Imperfect IVs only exist so that competitive players can
spend a lot of time perfecting them and feel good for "achieving" something that wouldn't be necessary to achieve if IVs were perfect or didn't exist to begin with.
Anybody can win by simply copying what is most common.
Something that the current system has not prevented from happening, at all.
The entire premise of Pokémon is to be the best Pokémon trainer. The EV system represents the way that you train your train Pokémon and the IV system represents their potential.
That's just your personal take. Pokémon has different premises, and not everyone cares so much about being or having
the best. Pokémon is an advanced rock paper scissors in which every Pokémon, and every team, is supposed to beat others while being beaten by some others. All you can do is try to build a team that can overcome different challenges and win as much as possible, but there is no best
anything because every trainer, Pokémon, team, and strategy is expected to be countered by something else, no matter how good they are, and even luck plays a large part. And if something is so broken that very few things can counter it, then it has to be banned or rebalanced accordingly because that's not supposed to happen.
Nowadays, the developers are attempting to make it ridiculously easy to have a competitive Pokémon without putting in much work. Now, you can hyper train a Pokémon at level 50 instead of 100 and the Bottle Caps needed to make it happen can be store bought now without having to grind for BP.
Sounds like you're worried about the competitive player base growing larger, as your VIP circle becomes accessible to more players and may be eventually contaminated by tons of casuals who didn't earn the right to be there. The only reason to perceive changes like no longer forcing players to level up all the way to level 100, or somewhat toning down other grindy and time consuming tasks as something negative, is because it feels bad that other players will be able to enter the competitive scene without investing as much heavy work and time sink as you do. But, as you can't possibly ignore, lots of players hack IVs, shinies, and all they want and build competitive teams in minutes using external tools anyway, so players building teams with minimal effort (which they probably wouldn't if team building mechanics were more fun and enjoyable) has allways been a thing.
I understand that some gatekeeping (because that's what it looks like) might be necessary in order to prevent an overpopulation in the competitive scene, that would somewhat justify the obtuse mechanics, but wouldn't invalidate the point about them being obtuse.