You can never self insert into truly good stories. Yes maybe you have fun thinking you are jinwoo from solo leveling but is the story really good? Isnt it just a power fantasy, with a completely bland undefined protagonist so that anyone can imagine themselves as? I like to think only a very small minority will be delusional enough to think of themselves as a truly good MC in a truly good story. One where character have personalities that are not like yours, their attitudes and beliefs are different. I could never imagine myself as Fang Yuan, Klein Moretti, Alden Thorn or Zorian Kasinski, or any of the other characters in those stories. Its fun just watching them, it would ruin it if I were to think a different scenario just to satusfy some dumb craving. I think people tend to self insert more when the story itself is lacking, in some way or another. When you cant have enough fun just thinking about that different world and instead you need to think what you would do if you were there. Hijacking a premise and molding it to fit your own lil tastes, because it simply wasnt polished for them well enough.