@LuffyKun
There are 2 rounds of chapters removal from Mangadex.
The first group, MerakiScans, picked up the manhwa and started translating 3-4 times chapters/week so that they can catch up with the raws. Once they caught up, they went back to translating 1 chapters/week because that's how fast the raws are getting released, and they release the translation 1 day after raws released, you cannot ask for more tbh. However, they were issued a C&D and had to remove all their translated chapters and stop translating the manhwa altogether.
The second group picked the manhwa back up, and started translating where Meraki stopped, and has been until 1-2 months ago, where the Mangadex staffs and several scanlation groups had a falling out. I won't attempt to summarize what happened. You can go look around to find out if you care enough to do it. After the falling out, the group decided to remove all their translated chapters from Mangadex as well.
@havelmom
Do you know why OPM gets an anime? It's a manga (Japanese). Solo Leveling is a manhwa (Korean), and no matter how popular a manhwa is, it is very rare that a Japanese studio will want to make an anime out of it because their audience is Japanese, and manhwa do not have an official publication in Japan. It matters not what free readers think of the manga/manhwa, we are not their target audience.