The writer has a lot of issues and, honestly, doesn't feel ready to write stories in English yet. There are a -lot- of grammar issues, and massive perspective problems in every single chapter.
As for the story itself.. the self-insert is a fairly successful novel writer (yeaaahhhh.. no) who acts pretty unnaturally given his reincarnated situation; the reincarnated part of his character seems mostly glossed over and forgotten. He doesn't use it for anything, and the relationship with his sister is exactly the same as in canon, even though there is an older, completely different person in the body of this character.
In fact, all of the characters feel extremely unnatural as a whole. People who should have no concept of technology or anime or anything just pick up on it without explanation and act like it's the most normal thing in the world. Characters' thought processes are unbelievable at best.
Very clearly written in one sitting, putting thoughts into words and then isn't properly edited, and it makes it feel incoherent and is difficult to read.
It's often written like the writer assumes we know what he's thinking and why he's thinking it, and jumps two or three steps in the buildup and explanation, only to land on something that feels completely out of place as a result.
An example would be the different characters sending information over the phone. How? It's never explained. First off, how are these technologically stupid people just sending "magic" and "swordsplay" over a phone? How is he receiving it? It's never even explored or explained a little bit, but just taken completely for granted and passed over. It's absolutely ridiculous.
Then there's the ghosts. He brings them cakes, but when the girl tries to hug them, she passes through them? Are they solid or not? The logic of the story's world is completely screwed. Not to mention that the kids weren't actually used for anything at all other than getting every character to say "G-g-g-ghost!" like they're Scooby Doo and forcing an interaction with that one girl. Even the set up emotional reunion was completely ruined by them just disappearing the second they saw her, and nothing further was explored about it.
Not to mention how the character learns "swordplay" by.. getting a manual about it(? somehow it changes to paper from his phone?) and then swinging his sword the same way 1000 times, like that is supposed to teach him anything. When you know nothing about the sword, you have a thousand things to learn before you even start swinging that thing around. Your posture, movement, grip, etc. etc. You don't just go and start swinging a sword and become a swordsman, and even then, swinging just one way isn't going to make you any better at anything; it's so silly.
The protagonist starts talking about opening up a restaurant out of absolutely nowhere. Like, it wasn't built up in any way, and the writer clearly just wanted to do it for whatever reason, even if it made no sense in-universe. It was justified because the character "knew a guy with a restaurant" and that he would get recipes sent over. Like that solves more than one or two out of a thousand problems with opening up a restaurant, and prepares him for that chaos in any way whatsoever
These are a few examples, but already this soon in the story there are even more I could pull from, and I'm positive it will continue throughout the whole thing.
Basically, it feels like whoever writes this doesn't live in the real world. Their logic is completely off in so many ways. It really feels like the writer has gotten too deeply integrated in the universe of anime himself and has forgotten how actual people think, act and speak, and it really shows in the writing. Overall, it just comes off as disconnected and childish.
I don't know why this story is rated 4.6. Either the negative reviews are deleted or you guys just have insanely low standards. 2.4 was already generous for me.
For the writer: Work harder on your basics. Spend some time figuring out your English grammar and read some well-written, published stories to try and get a better feel for how to actually present a decent story. Your ideas aren't terrible, but your execution is very lacking; especially for someone clearly wanting to make money off of this. It takes a lot of hard work to get good at something, and writing is no different.
Good luck.