Recently, when I was reading Ex Rank Supporting Role's Replay in a Prestigious School, I came across the realisation that it's one of the only stories with, what could effectively be considered a Return To The Past Story (it isn't return to the past, but it has some of the same narrative side effects), that treats the Butterfly Effect as a potential positive for the MC. To clarify, for most stories, when the MC ends up in a situation where they know the future and tries to change it, they start making radical changes that affects those around them, but get surprised when situations and people start being different, and it's usually treated as if it's to the MC's detriment. Making up an example, MC "A" Returns to the past and saves the lives of his (male, so that this is an OP MC action story) childhood friend/s from a rogue accident, let's say a drunk driver while they were pedestrians, that... let's say paralysed at least one person (and killed the others) so that they were seemingly killed later on by certain effects of the world-changing disaster the MC was fighting until he died. This helps the MC, the friend, and the friend's family. And most stories treats it as if the side effects from that end there, as a net positive. My issue is, that one change affects significantly more people than just those few directly affected by the change. If the paralysed person had a personality change from becoming paralysed (as they usually do), or suffered Survivor's Guilt if more people were with them, that affects most people they interact with in some way. What's more, if the Driver survived in both timelines, then it affects how they get treated by police and prosecution, as if the Driver didn't kill or maim anyone, then they can only be jailed for DWUI (and property destruction). If MC A and their Friend/s were in school, it affects everyone around them, from teachers to fellow students. This can affect decisions they make, from who they make friends with, to who they avoid and how easy it is to avoid people (and that's ignoring all the different romantic-relationship-related butterfly effect related changes that could easily occur due to that modification). But so many Fixes-The-Past stories don't touch upon how interconnected people actually are, nor how changing one thing can change others. A best friend in the MC's first timeline could easily become a hated bully in the second, or vice versa. A Teacher who was gentle and kind to those who were friends with a cripple could easily also be a strict hard-ass to a MC who doesn't, while another Teacher who was considered a strict hard-ass by the MC could be revealed to be someone who holds everyone to the same standard, regardless of whether or not they're physically disabled, and thus is more pleasant the second time round, where the MC actually gets to class on time instead of dawdling on the way to class with his disabled friend, expecting special treatment because the disabled friend can't move as fast as an able bodied person. This is all, of course, long before the disaster strikes, because I don't want to actually make that part up, but you get what I'm saying, right? Anyway, I'm looking for stories where they don't treat the Butterfly Effect changing things to be a significant surprise, nor one that's necessarily negative. Seriously, the number of stories that has the future change based on the MC's actions, but the MC only cares when it's to their detriment is astounding. Mother of Learning, and other Time Loop Stories, are not to be included, as they are Time Loop Stories instead of being Return To The Past Stories. Stories where the MC is, effectively, returned to the past, and thus only has one chance to succeed or fail, like Ex Rank Supporting Role's Replay, are allowed, however.
I would highly suggest jumping ship, the isekai genre is very broad and just means another world. Regression means the MC would have firsthand experience of the situation, transmigration could be a spurn of the moment and they would be a foreigner (which has a ton of pits which is not limited to: racism, exhalting a countries agenda or “modernism” etc.), and reincarnation which can be regression but not the other way around. That’s just a butchered explanation but basically I would suggest finding novels where MC is a Reader (like they read the events of a book and they transported into the book), they’re very prone to the butterfly effect. To what agency the MC feels regardless of they’re OP or not is something you still have to find a title for. Trash of the Count’s Family, is something I will always recommend for the fact that’s it’s a well defined found family BUT also that he doesn’t have an episode about how he doesn’t see this as his reality and need some sort of tragic event to spurn that. Omniscient Reader’s Viewpoint, is of similar effect and is very shounen (targeting youth male audiences ex. Naruto, Demon Slayer). It’s a feels good story with an OP protagonist to some effect. Found family is also a prevalent theme but I think the philosophical trip of “what a story is” is well executed. I still have my gripes with these stories but I rate them highly. Also while there is no tag for found families on NU because it’s more of a cliche the reader assumes than an actual element present in the story, is because to what intimacy it offers the reader. They give you a reason to care about the supporting cast, and how the MC influence them is just... it’s amazing.
Give Dungeon Hunter a try...kinda fits your criteria as the MC dies and starts again with the previous knowledge...and his actions affect both his future and that of others
I agree with TCF and ORV, it is knowing everything and know it will affect the future, they try to maintain the butterfly effect well, so they can strategize well, they both have one chance I dont know other tho. Maybe goldern days? (shounen ai tho), he need to change past to help his grandfather friend, which affect everyone! In the end it turn out different ending from first timeline. He doesnt have an advantage tho..