There's a few things wrong with this novel.
1) The MC - Isn't defined properly at all. Only traits I know of so far are being over powered, handsome, and that he's hiding a trauma of some sort. Other than that, I know nothing of his personality other than he dislikes school. For some reason also, right off the bat, he is seen as the "leader" of the chat group, though making him an Admin certainly allows him to be in a sort of "superior" position, it is known he only has that position because he joined first. He did not earn the respect nor trust of the people in the group and has only talked to them for a total of 2 hours before they start seeing him as a leader and follow his every command. It also seems like the author is going to define the main characters personality through flash backs which is something I personally dislike. Also, the very fact you made him a universe buster level being right off the bat is a turnoff. I won't be expecting any challenges for the protagonist to overcome besides melodramatic ones.
2) World Building - The world he comes from is very random. It isn't thought through at all, and I think that the author expects the reader to know what he imagines within his mind. Besides the fact that there are universal level beings that go to school or something, I know next to nothing about his home multiverse.
There are a few more problems, such as power creeping, character interaction, character inaction, plot devices in the form of random "items" the protagonists home world conveniently has for every issue that pops up during the dimensional trip, etc.
The writing quality is decent, but the author lacks a lexicon with more variety. Honestly the idea of the novel is pretty amazing and has a lot of potential, different beings from different dimensions coming together in one chap group and going through quests together, helping each other, and interacting is a concept with a lot of potential, but the sheer difference in power between them along with the extremely fast bonding is a turn off. Lacks a lot of depth, but has potential for sure.