Apologies for accidentally deleting your ask, anon! I’ve been mass-deleting a bunch of weird spam from bot accounts, and unfortunately, your message got caught in the crossfire. Whoever you are, here’s my answer:
Are you interested in a Solo Leveling and Avatar crossover? ;)
Short answer: YES!!!!!! I’m very interested in an Avatar/Solo Leveling crossover AU where Spider discovers a mysterious program that lets him level up and kick ass. That said, he wouldn’t be a carbon copy of Sung Jin-Woo (because that man is the GOAT), but Spider would still be a total badass in his own right. With his natural stamina, agility, and strength from years of running with Na'vi, he’d become seriously overpowered with every level-up. Maybe Eywa has her own version of dungeons that let him boost his stats, and over time, the kid bulks up and hits a growth spurt. Eventually, he wouldn’t need his breathing mask because his body would evolve and adapt to Pandora’s environment with each level gained.
-) Training in secret while balancing his everyday life.
-) “Dungeons” manifested by Eywa, such as corrupted forest areas, rogue wildlife, or sites that need purifying.
-) His power increases, and Spider encounters more RDA soldiers and begins sabotaging their operations using what he learns to ruin their plans using stealth, even going so far as to kill them. His first kill leaves him with nightmares and crippling guilt because this isn't what he wanted, but it's too late to turn back time. He has to protect his home.
-) Internal struggle over his identity, which involves Spider sometimes feeling a little detached from his humanity. Spider is still mostly the same (mostly), but he's colder and more serious to the point that his friends start to notice and jokingly compare him to a boring adult. Spider chuckles at that, but his smile doesn't quite reach his eyes, and his laughter is forced. He feels like he's pretending to be himself, and it's driving him crazy. Kiri, Lo'ak, Tuk, and even Neteyam are all just kids, while he feels...less and less like his age.
-) A dangerous dungeon triggers a major power boost but also reveals part of Eywa’s plan, hinting that she is preparing Spider for a larger threat and that Kiri is the key to ending it. He'll need to grow even stronger to protect her.
-) I don't see Quaritch surviving for too long in this au. The scene in Way of Water where the kids are being threatened by Quaritch and the Recoms will probably end with Spider allowing them to kidnap him so that he can be taken inside their base and just straight up slaughter everyone before they can interrogate him. Afterwards, Spider sifts through the gore and blood to steal all the information before setting everything on fire and cutting off his father's head to dump it on Jake Sully's doorstep with a note that says, "My debt has been paid in full. Best of luck to you, Mr. Sully. Goodbye." Dark? Yes. Traumatizing? Yes. But Spider has changed from that kind boy who would never harm a fly. Maybe he'll raise his father's spirit and the spirits of the recoms to serve him. Either way, he did his part and he travels Pandora to grow even stronger while occasionally popping up to help the Sullys out of some more craziness before fucking off again to do his own thing.
Okay, this has gotten long and out of hand, but you get my drift! Does this plot make sense? Absolutely not! Still, I've been a mega fan of Solo-Level since it first came out, and the anime SLAPS. Spider would have his reasons for obsessively leveling up, and it starts off with him wanting to protect his home and friends...and then his desires slowly start to shift outside of just acting like an attack dog.
Anyway, hope this answers your question, anon!