@OrlonKronsteen Ascension diffulty changes a lot depending on the difficulty slider. If you're just planning to explore it, you could play around with that and find a setting that suits you. There is, indeed, quite a difficulty spike compared to even the harder SCS battles in my opinion, at least on tactical or insane (which are the difficulties I have experience with). For me, insane ascension is so tough that it kind of warps my approach entirely around the endgame, where I consider party composition, itemization and the like from the very beginning just by looking at the biggest of the ascension battles, which is a bit too much and the reason I rarely play with it. Others, of course, don't ever even play the game without the mod and know of several ways to achieve victory there (and it's true that SCS Amelyssan without ascension is not all that hard and can be a bit disappointing - in a full SCS run without ascension, I think that the hardest battles are propably in Watcher's Keep).
Regarding the idea of no-reloading another game: I do own BG3, but after initially playing for a few hours I suddenly lost interest in it (I can't even quite say why, exactly) - I am planning to return to it at some point once I am able to build up the motivation and time (can't play it with a podcast in the background like I do for BG), but propably mostly to explore the storyline and characters, not to get to deep into the game systems (as I didn't enjoy combat too much), so it's propably something I would not want to no-reload any time soon.
As for Pathfinder, I don't own any of the games and had so far not too much of an interest in them. I have lead around 4 sessions of P&P Pathfinder back in the day, so I am not completely unfamiliar with the ruleset, but I am not super adventerous when it comes to getting into new games and playing no-reload right away.
As mentioned over there, PoE2 is currently the one game I'm looking at that I may want to try in no-reload mode at some point. Doesn't have to be any time soon, but I would be fine with giving it a try in the near future as well, and, of course, a few other people to share experiences with could motivate me to do so (no pressure if the interest in other games is bigger, though). 2 playthroughs is not exactly the level of familiarity I would usually like before doing something like that, but I have experienced all parts of the story now, so I don't mind focusing on the game system for another run (though my approach and party would propably be terrible by the standards of anyone who is actually knowledgeable about the mechanical changes to the series).