Martial World is a long webnovel that I actually think encapsulates a lot of features of the cultivation genre, though it does have its share of brainworms and anime bullshit, like the main character having multiple wives and a few problematic scenes involving them. It does spill a lot of digital ink on the progression of the main character through cultivation realms, which is the shit I live for. It's the long-running shounen version of the genre, imo (while I have some titles under my belt, I don't know too awful many).

I haven't read Grandmaster of Demonic Cultivation as mentioned, but I did watch the donghua and found it quite good, though I don't remember anything about it's progression system. A great option for a more drama-oriented entry. BL (I also only know danmei as BL).

I remember really liking The Dragon, which is GL, though it may also be more a fun and dramatic romance set in a cultivation setting than a cultivation novel.