Solo Leveling sounds like the most generic shit possible but that's typical for most Korean webcomics.
Tldr for first episode is that the modern day Seoul(?) has demons invade and from that people discover magic and fucking dungeons appear, which must be cleared or the demons invade through them into the real world. And every person has a magic core that says how OP you are, and that core never changes so you are absolutely fucked if you rolled low on birth and want to be an adventurer (legit they have "modern day adventurer guild" which basically makes the whole dungeon delving a corpo gig with F-SSS adventure levels like it's fucking Monster Hunter). The hero of course has retardedly weak magical core but despite it he tries to be an adventurer to.... <pulls a card out of a hat> his sister needs to go through college and his mother needs a surgery that can't be healed with magic for some reason out of the insane reason is that you can make it big in that gig, as if there isn't plenty of saner ways to make money that won't get you killed, especially as he is literally level 0 and he risks his party more than help them with nearly no gains until now.
The show pulls a MHA of "the hero is weak but he is smarter for it because obviously people who are good at fighting won't actually invest in learning about the world" which is usual loser cope. Anyways the guy gets with his party into a super special double dungeon, they get into a puzzle boss that, obviously, everyone besides the hero are too stupid to realize and do correctly. And after averting a total party kill the hero gets fucked other by a party member and sacrifices himself for the other members back to safety. The hero dies while cursing the world, except not, he got super special
mystery skill from our best friend "voiced menu lady". Next episode he is okay because getting the skill rezzed him, he is in an hospital and he is checked for having his power level increasing, and of course it's the usual bullshit where it haven't increased and I just got bored from there and watched Gintama because it was obvious he'll realize he can now level up his core and beat the staceys and the chads.
It's just godawful world building that might have been unique when it was new, but is bland now. At least shows like GATE realize how retarded they are and had fun with it. Here we have modern day with people entering a dungeon in a fucking sweatpants and wielding daggers, rather than a tactical vest and an AK-47. It's so lazy and pathetic.