Anyway, this seems to be focusing on a reincarnated individual from our reality whose magic use ability is somehow "inside out" compared to the norm, so he cannot utilize the standard methods of obtaining increases in power. At first he was not aware that methods existed that he could utilize; knowledge of such methods appears to be uncommon, and only work for a small segment of those considered to be without magic ability, those whose magic ability is actually inverted from the norm rather than actually being non-existent; first, someone had to discern that he actually did have magic ability, albeit of a non-standard type, and the one who did this knew of a means to increase it. By Chapter 11's completion, he has been successful in beginning to increase his power, but has reached a plateau until he can afford more expensive power boosting treatments.
Prior to learning to increase his power, he was dealing with the reality that those of low/non-existent magic resources in this society are treated like dirt. "Might makes right", where might is measured in magical ability, those lacking in such ability are considered fair game, and have no legal protections against others manipulating things via their magic abilities.
He found a means of advancing himself financially anyway, by partnering with a lingerie merchant; apparently, brassiers, etc., were unknown in this society, and he knew enough about their construction to successfully create working versions.
However, being of little magic power, they were targeted by those who would usurp their operation.
Fortunately, the initial attempt occurred while a female member of a powerful family was shopping at their shop, and she intervened.
She also knew of a means of increasing his magic power.
She suggested he join an association to improve his social status and clout; somehow he knew nothing of associations, which seems odd if he grew up in this society, but I don't recollect if he reincarnated as a child or as an adult, in the latter case such ignorance would be more understandable.
Anyway, she arranged for her family's association to extend an offer to him. At which time the knowledge of how to increase his magic power was provided.
And it looks like others may be getting into the act; high rank females being the clientele of his shop, brings him into contact with them in an environment that favors the impression he makes, even to those who seem permanently grumpy/haughty/arrogant/convinced of their superiority.
He attempts to defuse situations where there is conflict if possible, while not knuckling under to those exploiting their higher status.
I suspect there are errors in the above summary; not suspect, I'm certain of it. But, hopefully it makes some things more clear. Mainly things omitted, but there are some where I may be misinterpreting, but still close enough that you can spot the misinterpretations when you get to the relevant sections of the story. Given the timing of updates, some of my memories of this are hazy.
So, yes, rather different from the standard Isekai setting.