Agreed here, so where I stand ends up being based less on who are good guys here (spoiler: no one is) and on 1) which system seems to create the best football and 2) which system pays the actual players more money. My conclusion on #1 is that the current system rewards the best football better than an ESL system. On #2, it feels like a salary cap and cost controls are part of the motivations for the move, which makes me suspicious of it, though balanced by perhaps better monetization of football money flowing through the system.
I'm suspicious of the ESL for all sorts of reasons. But I don't feel like we have enough information to say whether it will improve on the status quo on either of these counts. What I would say is that the status quo is pretty shit when it comes to the former and that UEFA and the national associations are not showing really any sign at all that they are interested in or capable of change. In terms of creating the best football, the status quo is basically that there are five big leagues, three of them have been completely uncompetitive for the last decade (all with about 9/10 titles won by a single team, and with the hegemon tending to just buy the best players of any team that challenges them), one has been a duopoly, and one has had real competition but has been trending towards dominance by the sovereign wealth fund of an oil dictatorship. That is paired with a UCL system in which the majority of the games are largely meaningless group stage matches, the R16 usually has a couple competitive ties, then things get interesting in the quarterfinals but half the time the tie ends up turning on a decision made by a poorly implemented VAR system.
Would ESL make it better? I don't really know. Its going to widen disparities between ESL sides and the rest, so in leagues with only 1-2 ESL teams its only going to further entrench a lack of competitiveness. But in leagues with 3+ ESL teams it will distance those teams from the rest while likely increasing parity among that group. I certainly think more teams would have a realistic shot at winning the title in the Premier League in any given year, for example, than under the status quo. More importantly, the real promise of the ESL (whether it would realize this promise is another matter) is that it could create a league in which there are a very high number of legitimately really good sides, with an even enough playing field that a large number of them could actually win the title in any given year. If they pulled that off (totally uncertain, but possible), I think it would be a huge improvement in terms of creating and rewarding the best football.