Some mainstream studios you might want to check out are Dontnod Entertainment (Life is Strange, Tell Me Why), Red Thread Games (Draugen, Dreamfall Chapters), The Chinese Room (Everybody's Gone to the Rapture), Campo Santo (Firewatch) and Fullbright (Tacoma, Gone Home). There is tons of quirkier experimental stuff on Steam and Itch too. Note that some walking sims are more about exploring the environment and there isn't much dialog, while other ones feature more conversations. Dontnod tend to be more on the conversation-y end if that's what you're after.
You could also check out point-and-click adventures, which are a direct descendent of IF. They require a bit more puzzle-solving, but the pacing is often very good in modern (post-2005) games and it's a nice way to experience dialog-heavy stories. A good place to start might be older releases from Daedalic Entertainment or Wadjet Eye Games, perhaps.
By accidents of history, visual novel as a genre is strongly correlated with anime aesthetics and tends to focus on certain story genres that may or may not interest you. However, there's no fundamental reason for this, any more than there's a fundamental reason why "cartoons" in the US became strongly associated with "for children".
Quality is definitely also mixed, as the bar for entry of this style of thing is low. But that also means there's the sort of vibrancy and experimentation you get when there's virtually no "commercial market" functioning as a taste-maker by overwhelming all the smaller groups with big piles of money and raising the consumer's expectation of quality beyond what they can compete with.