Nizze In regard to contracted originals, I agree with what you say regarding quality of some stories. These stories aren't show casing the quality originals that are here.
Believe it or not, there are stories here with impeccable grammar you can read for free in its entirety, no spirit stones lost. I've listed some below based on grammar quality and solid storytelling (nb: some are BL), which I feel is at 90% - 99% top quality.
There are a lot more on this site, which carry high standards. I have a whole library filled with quality hidden gems.
All the books I've mentioned are well written, and most are from anglophones. However, what they all have in common is none of them are contracted. I feel they are more than worthy enough for one at any site.
In short, it's a hunt for a good quality story, and especially those freely available. Some contracted books need revision for technical quality improvements.
Not all contracted books are badly written by the way. Ball of Nothing was a story I didn't spot many technical issues. Edit: I found The Hitting Zone was also a good read and I didn't spot too many grammar issues.
So, my complaint to @webnovel_staff, improve your search function and give non contracted Originals a proper recommendation slot on your homepage. None of this daily update BS. If the story has over 50K worth of words (novella length) and screened for basic quality (e.g. filter out/flag grammar errors, NSFW content...), it should be enough for a feature, so readers can find new quality works and enjoy.