As for MC being mega rich and crashing economy/causing inflation with Japan printing money to pay him - he's rich for a person, but we should treat him more like a corporation.
Let's take his monthly take home from chapter 2 (2 billion Yen in panel, but lets go with 20 billion because translation also said that, and i seen this number in this thread - so we can assume this to be some sort of best case scenario/overexaggeration just to prove a point).
Lets also assume zero taxes (i know they were mentioned in this manga, but w/e), and zero costs for MC - so pure profit, what he gets from the dungeon is what he brings home.
Lets change the setting a little, and instead of adventurer and magic stones lets use oil tycoon (with super cheap to explore field) and well, oil.
20 billion Yen is roughly 130 million USD. A barrel of oil is roughly 60 USD at the moment.
130 million USD is roughly 2.1 million barrels of oil.
Global oil production is around 80 millions of barrels per DAY. CBA to look up accurate numbers, but Japan's usage is around 3-3.5 mil per day according to chatgpt, UK was using 1.5-2 mil per day 10-20 years ago.
Sure, he's insanely rich - more money that he can reasonably spend w/o throwing it away or buying a new yacht every month or so. But the impact on economy - he can supply Japan with oil and it's products for 16 hours or so.
So lets do something dumb - lets say MC is being paid only 10% of what he brings. He's suddenly producing 20 millions of barrels a month, in a world that produces 2400. So now he's providing what, 20% of Japan's needs? This makes him a serious player, at least in country scale.
He's being paid 1%? Well now it's 200 million of barrels per month. Now we have a global player - but still, at around 2/3rds of Russia or Saudi Arabia.
And remember, to even get close to a nation's power, we had to basically increase it by 1000 (him being paid 20 billion instead of 2, and being paid only 1% of what he produced.)
I assume 20 billion is misstranslation (drawing in panel clearly says 2 billion) and some people confused Yen with USD. If MC really earned 13 million USD per month, that's still fuck you amount of money TBH.
But well, author probably pulled this world's economy out of his ass, and his bank account is not connected in any way to his economic impact.
As for his relationship with his ex-gf? I don't like the fact that she's being portrayed as nice person in flashbacks. If she was, she should be at least a little interested in him or his surroundings (Hell she never visited his apartment? She never asked a question about his work, even if he never told her himself? She never noticed a restaurant she's in in high class?)
I get it that it was written this way to make a revenge story (basically a variation of i'm being banished because of my useless skill, but secretly i'm OP) and her a golddigger, but there's no basis for her being a golddigger in the past, and she's too dumb to be one (real one would spot expensive clothes or restaurants from a mile away).
And MC is being too nonchalant about it. I get it, he wanted to retire anyway - but he completely got over it in what, 12 hours? (night of drinking at the restaurant + hungover untill he met FMC in the park). And for a revenge story, he has basically zero desire for one. That's a bit unnatural IMO, that he has ZERO ill will to people that have intentionally wronged him.
I'm reading it for gyaru grooming anyway, so who cares.
