IMHO first season of Solo Leveling was so bad that I honestly don't know what could possibly justify watching more of the same. Story-wise it is below mediocre, being nowhere near quality of predecessors exploring life is a computer game concept... If Solo Leveling is "one of the best anime of recent times" then we are in a bad recession...
https://ecency.com/hive-158489/@onlyjob/ore-dake-level-up-na
Well, I don't think Solo Leveling's strong point is its story, but rather its fights, which make it entertaining. In that it's a 10/10 thanks to its animation.
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)
"It seems to me that you just don't like books". (Let's not jump to conclusions, shall we?) Well, there are different books, and different isekai. I have nothing against isekai but Solo Leveling is awful isekai, because there is no character growth (just levelling-up), and no story (just playing Diablo-like game, with endless dungeons, monsters, etc.). Fights are boring and pointless. Absurdity of the setup is over the top, with game inventory so main character pulls stuff out of nowhere, literally; and instant healing showing that in that game-world there are no physical limitations whatsoever. So all plausibility goes out the window and viewer needs infinite suspension of disbelief to endure all that nonsense. And what for? For nothing, apparently, as nothing matters any more after gamification of main character, as everything is just the game. Surely unsophisticated viewers are easily impressed by graphics veneer that can't hide the fact that story-wise Solo Levelling is one of the shallowest anime ever made. (Where can I find cheat codes for life?)
Sword Art Online had its own problems but it have plausible setup, believable development, actual plot and everything much better than Solo Leveling that appears to be a massive regress in sophistication of story and storytelling. Jobless Reincarnation and Re: Zero have much more for viewers than Solo Leveling, if you know what I mean.
"It seems to me that you just don't like books". (Let's not jump to conclusions, shall we?)
Can you really claim you like meat when all you eat is Wagyu beef and you still find something to complain about? :o) All the isekais you've mentioned in your posts are not only exceptional, but also atypical. They are special because they either lack usual traits or twist them in their unique way.
because there is no character growth (just levelling-up),
In Solo Leveling leveling is not really all that important - only the fact that he can level while other hunters cannot. However his leveling does not turn him into someone else, his goals remain the same as when he first entered the gate, he just gained confidence that he might be able to actually achieve them. The "game like" elements that you so inexplicably despise are part of actual game - all the gates he enters with keys and also the penalty desert are game with its own rules (fundamentally different from normal gates that are part of reality), created by the system creator to help him grow because... (will be revealed in third season). Also the story is not something that happens solely to push him forward. The world does not revolve around him. Other characters have their own lives. He learns (and so do the viewers) about new facets of reality that existed independently from him as they become relevant in his life. Comparing it to SAO, where the events seem forced just to keep the story going and allow protagonist to be a hero once more.
Re:Zero - I liked the concept of his power - both cheat like and pretty useless in the same time (why didn't he die for real from PTSD?) and there were hints pointing to deeper interesting story around Beatrice, however I could not stand the idiot Subaru (and Emilia too, tbh). I'm surprised I survived through the first season (I'm just allergic to cringe elements).
Mushoku Tensei is one of my favorite stories, although while I certainly watched the anime, I remember it more from the manga(s). I disagree with the following:
Past life experience don't help him much
Rudeus despises his old self and tries to live the opposite way. His past serves as a reference point to guide him away in his new life (and it is also one aspect that makes it atypical - normal isekais allow protagonists to redevelop sanitation appliances, Japanese cuisine, sometimes even whole modern industries).
half a minute or so of almost each episode is dedicated to "pervert factor" like obsession with underwear or groping, for no good reason, completely unnecessary, adding nothing to the story and just ruining the taste and style
That is important part of his new self and what makes him true resident of new world - his father is also a womanizer, and while he still feels some reserve towards such behavior, he ends up with three wives.