I think the old grapple rules are bollocks. Poorly working and exploitable.
I think the new rules are better.
Who is right? Probably not you. But your mileage might vary.
Edit: and I have made some arguments. You just need to scroll back and read them.
I have read them. None of them are cogent arguments imo. And you're definitely wrong if you think the old rules were "bollocks", especially given that the reasoning you state over and over, is about an entirely fantastical and nonsensical corner-case setup that could, potentially, happen, and how awful that is (or rather "might be in theory", if it ever actually happened beyond gimmick games and the like).
You never even acknowledged the legitimate class-feature and other people's spells approaches to this, nor that even without any of that, this gave Martial PCs a real option, that made them mildly competitive with casters in one particular way.
It's just extremely funny that we get people like you saying it was a "rule exploit" (which is demonstrably false, there's no exploit, no misunderstanding of the rules involved), which is demonstrably false, whilst claiming I'm wrong.
I’m not sure how a rule that matches both spell debuffs and to-hit rolls (which are cornerstones of the game) can be poorly implemented. If you are against those mechanics are you against them across the board, or just with grapples?
What do you mean "spell debuffs"? Are you talking about CC spells? Which are fire and forget, ranged, don't require a to-hit-roll, just a save and expose the caster to zero risk in most cases?
Because, yeah I definitely think it's wrong to make a risky option that requires continuous input from martials to be only equally or less effective than a fire-and-forget spell from casters. 100%. That's obviously ridiculous and unbalanced. Even if you can use it repeatedly (but it costs you repeated in terms of needing a free hand and an attack).
And it's "poorly implemented" particularly because there's no reasonable way to scale it, whereas before there were loads (most of which made complete sense, like an ally using the Help action to give you Advantage on the STR check). In particular there's no way for martials to scale it. I also think the auto-escape feature is excessive - with a higher DC that might be less of an issue.
Re: "to-hit rolls", dude you're being super vague which is unhelpful, but are you referring to Shove? Because yeah I think making Shove vastly easier to land for basically everyone is bad for the game (and vastly more AC-dependent), and particularly bad for grappling from both directions. Shove was already not a great rules design in 5E. The 1D&D version is worse.
If you think just because the numbers match a standard, even though the rules are completely different, it's automatically fine, I have no idea what to say to you beyond "That's not a logical way to approach this".