I think this could be categorized as an "survival isekai". I also enjoy reading this series, though I don't think this is the type of a world you'd wanna actually experience yourself like MC.
The leveling system really is convoluted, at least in my opinion.

This has been pretty decent so far. Though MC being just a support is kinda disappointing for my taste. Hopefully he takes a more active role later on.

Gotta respect this protagonist. He was actually prepared and planned ahead, to kill his own bully. Way better than those stories where the bullied protagonist just commits a suicide etc., than tries to make things better for themself, even if it's by murdering the bully in a forrest using a spiked pitfall.

I honestly don't get MC's abrasive feelings towards Nathalia. (It really makes no actual sense in this story)
Pretty much every deal MC has done with her, has been a great one for MC. If anything, MC should treat her like a good friend. Besides she's a cutie, especially when she smiles while she eats those sweets.

But it wouldn't be incest, nor would they be step siblings.. Dunno where you got that idea. Either you don't know what those terms mean, or you have misunderstood what you've read. They have no blood relation what so ever. So even if she was adoptep to the family, there would be no moral problem for them to start dating later on. (Even though that's not what I was implying.)

It really is a huge plot convenience, how MC keeps ignoring his messages, and hasn't repeatedly yelled out loud the name of the murderer..

Honestly the fact that MC would tell the guy who took over his body/life, the safe combination for all the important notes regarding future plot of his manga, is a huge plot convenience that just doesn't make any rational sense..

Besides that, this manga is glossing over so many other things that you just can't overlook, if you take over a new body, but you don't have any of the old memories of that body..

Every person, every relative/family member would notice that you're a different person. From other peoples perspective you'd be a victim of amnesia.

Also, just because you can copy a style, doesn't have anything to do keeping the plot, and so many other things as interesting as before.

But other than that, I guess this is a pretty fun read. I just think the art style, is way better than the writing itself.

Honestly though if MC was smart he'd ask his parents to adopt her, and make her part of his family.. No better way to stop her becoming a mid-boss, than for her having a family that protects & loves her

At least give your kid a real sword if he's gonna fight an actual monster, jeez..

My educated guess would that they are the same person. Easy job for a god to reincarnate Kanami (and possibly her whole family) as nobles/aristocrats to that world, decades before, so she would be 15y(?) old by the time MC transfers to that world. Except her memories would be sealed here.

It's actually somewhat expectable "plot twist" if you think about it, especially if those two are "soul mates", and they're always destined to meet where ever they go.

Wasn't his MC supposed be an expert of this world? And I mean his knowledge regarding the demon lord's/bosses? How he can't recognize that one of the demon bosses is right in front of him? How embarrassing.
It's was kinda the point, that he won so far because of his speedrunners knowledge, but now he's at the mercy of his enemy's stupidity. He could be killed instantly if that slime wanted so.

And yeah, it's possible that MC is just faking it (which honestly doesn't make any sense, since he's constantly in such a vulnerable position).

I assume it's a trait that sounds good/positive for you, but instead you get "scammed", like the trait itself is a "trap" to waste your points/resources..
Like MC's "The affection of spirits". Sounds helpful, but you might get eaten instead..
But then again it's possible that in the future it's revealed that it might an OP trait instead.

I don't really care for the art style. It's a bit messy for my taste. I wonder if this is the same artist as with that cooking isekai manga, where the guy gets a fenrir to follow him because it likes his cooking so much, and later he also gets a slime named Sui.. I can't bother to check the name of that manga, well regardless..

Also, this protagonist smells like the type who doesn't have the mental fortitude to be able kill bad people. The drunken part was a totally missed chance to make this protagonist look like a proper badass. Instead we got him being a passive gag-puppet who only can dodge every attack that comes to him.

It's not a terrible start, but definitely it doesn't get my hopes up either.

Also, it feels like a plot hole, when they didn't properly explain, how this villain dude got a hold of this trading company, that has even legal inheritors in line for succession, and this guild master didn't really help either, and it has already been 3 years, since this situation's been going on. Just seems like a situation that couldn't realistically happen in any way.

Wow, talk about an unsatisfying ending for this arc.

If that villain survives I hope the author accidentally steps on a dog turd, and breaks his/her ankle (at separate occasions).

LAME

Why would he only target the puppets? Wouldn't it make most sense to target the one controlling them also..?
Oh wait, let me guess, this author doesn't have the balls to make our MC murder a cute looking psycho b1tch?

ONLY ONE WEAPON? SERIOUSLY!?

This dude is a shame to all adventurers everywhere. What a stupid newbie mistake.
Seriously, this seems like a HUGE lazy plot convenience.

This MC's low intelligence is honesly a huge turnoff regarding this manga.
This would be so much better if MC was smart enough that he wouldn't be taken advantage of.
Now it's portrayed like a talentless idiot won at the lottery, and the people around him take advantage of his gullible nature now that the money is around.

You don't have to be an idiot to understand how much time and effort it takes, to draw/create a manga, let alone one that is so good it gets published..

So considering all of that, why would you make a manga about a protagonist, who's a clear pushover, and a gullible idiot, for being taken advantage of..
(I know that if this was first a light novel, and it had decent sales, then it makes sense, to make this into manga, from purely that perspective)

Maybe it could be explained if MC didn't know that thing's worth (honestly, he should be informed enough beforehand, knowing it's value, before showing it to the guild),
BUT, he was clearly explained, how it was a "national treasure", worth 100 golds price.. And they even said how much it had the potential to earn..
If you as the author want to make your protagonist look a like tool, that's easy to take advantage of.. Clearly you succeeded author.

I will never, never understand why anybody, whether it's a LN author, or a mangaka, would wanna make a story about an idiot like this dude.
Sometimes I wonder if japanese people just like reading stories about these pathetic, dislikable protagonists.