It seems to me that you just don't like isekai. I on the other hand love it, especially when protagonist has to grow to power rather than to have it from the get-go. So it should not be a surprise that I completely disagree with your assessment :o)
Solo Leveling belongs to subclass of isekai, where Earth is turned into "other world", but other than that, it uses the same concepts. Item box, private worlds, teleports, healing and magic in general, melee weapons with destructive power of nukes etc. are pretty normal for that genre. And once you make an assumption that magic = technology, then isekai animes are not much different than Ghost in the Shell, Bokurano or Evangelion.
In your post you've compared it to Sword Art Online (you also mentioned Gantz, but I don't know anything about that). Yeah, there all the "magic elements" might seem more plausible, because it is a game, so anything goes, but where Solo Leveling beats SAO is plot and character development. In SAO Kirito is basically a disaster magnet - whatever bad can happen, it happens to him or to people he cares about, the fate requires insane levels of heroism out of him and he delivers despite being supposedly just a regular teenager. Other characters also don't have much nuance. Don't get me wrong, SAO is great and very entertaining, but there are no normal people there, people that despite "having powers" also have normal lives and problems with money, adolescence, opposite sex, government, health, social hierarchy, mental predispositions, people who thought themselves strong that break under pressure and the opposite, those who still fight despite being weak when all hope is lost. Yes, Jin-Woo has incredibly thick plot armor - something that is more visible in anime than in manhwa. Also yes, a lot of bad things happen around him, except in most cases the events are bad for others rather than him, plus if it was Kirito then every gate would be a red gate where he would have to sacrifice arm and leg to protect his harem :o)