Over the years, there have been multiple anime that have done exceptionally well globally despite being not as popular in Japan, and Solo Leveling may just be the latest addition to this list. Anime and manga have begun to acquire an even more diversified fan base in recent years. This shift is reflected in the various languages dubs and translations are readily available in as of late and the overall increased accessibility of anime and manga.
It's absolutely not an isekai, though it's definitely part of the supergenre of "incel with an irl video game HUD gains infinite power and concubines". It's actually more like the founder of the subgenre that became very popular in manhwa of "weakest incel in video game reality does extensive grinding and gains infinite power and concubines," a cousin of isekai. It's a very fine distinction.
It's also fucking garbo. It has the classic problem with its capitalist ideology of losing all sense of scope and goals that aren't "grow more" and just escalating into meaninglessness.
"Grow more" for some reason made me think of that one trump kid.
Baron, the largest son
I hear he ate some of the smaller ones.