A Webnovel that manages to get adapted into Light novel, Manga with great wuality and Anime with great animation, usually means it has really good story and very popular at that and the studio is believing in it.
A Webnovel that has good Lightnovel and Manga, but not so good anime adaptation, usually means that the Anime is just used for promotion for thr manga or Lightnovel.
A Webnovel have Good light ovel and great manga, but no anime, usually its not good enough to attract lots of audience.
A Webnovel have good light novel but not good enough manga, then the story doesnt attract that much audience and they couldn't invest in the manga.
A Webnovel that has good light novel but no manga means it doesn't attract enough people to invest in manga.
A webbovel that doesn't have good lightnovel simply means the story are so bad or not popular enough, they couldn't even invest in Lightnovel.
There's some exception when Webnkvel that have Lightnovel get adapted straight to Anime. Then the manga was made After the anime. Re:Zero got this treatment back in 2016 because it was so popular, the anime publishing just fully believes it.
There are also exceptions when WeBnovel that got Lightnovel have not so good manga, but got Anime adaptation that is great and worth watching. Mushoku Tensei got this treatment because the anime producer found the lightnovel and likes it. Mushoku Tensei's manga is so horribly bad and not that faithful to the novel, you mgiht check it, but just consider it doesnt exist. Only the novel and anime were necessary.
And remember, majority of webnovel don't get adapted even to lightnovel. Those that do are in the 1% category.
Webnovel aren't inherently bad, they're just mostly bad, bevause anyone can write anyhting, and most people are not that good in writing.
Still, Webnovel taht couldnt be adapted into light novel can explore unusual and unorthodox and uncommon topic that couldnt be explored or very uncommon in lightnovel, manga, and anime.
Altough finding those stories were like finding diamond in hay of stack, instead of finding diamond, or a needle, most thing we found dozen of haystack, most of them were very low quality haystack, and sometimes horseshit.
So i stick to adapted stories for quality assurance.
By the way, my tips for quality anime that doesnt bog you down with episodes :
Anime movies.
Not movies from anime with episode, but Original Anime movies. They have the same duration and pacing as movies, which is around 1 hour - 2 hour, depending on the anime movie itself.
And because it's only 1-2 hour, which is worth 3-6 aniem episode, the quality is condensed and you get better average experience than watching the average anime with episodes.
Its pretty much what japanese do when theyre tired of watcing episodes on TV and didnt like commiting somtme time reading manga/light novel, which tend to be episodes long.
They exclusively only watch original anime movies on their local Movie theater, so they get 1-2 hour max on highly condensed stories and won't be bothered about next episode or anything else.
This is what i woudl reccomend you to do if you have some form of home theater. Just watch original anime movies, and enjoy being free after it was over.