Don’t have much to offer on this I’m afraid. I don’t really publish online. I’ve only ever used WP, which I’ve retired from.
From what I’ve seen, Royal Road, WP & AO3 seems suited to your type of story. I know some writers make Wordpress websites and share their writing there 
I hear that is a negative place full of elitist males who severely dislike anything that isn’t to their liking…and women.
That’s why I ain’t going…again.
That is more fanfic-centered. I no longer write fanfiction.
Exactly!
I just upload my finished books to Amazon. I have one posted on Wattpad, but I sell that one at a reduced price. Amazon pays me a little every month from people who read my books through Kindle Unlimited. None of my work is posted anywhere else. ¯\_(ﭢ)_/¯
Ah, so you are self-published?
Awesome and I am glad that you are getting out there!
Congrats!
Write wherever the heck youre comfortable. All these places have their pros ans cons. You could even post across multiple sites
How much do you get paid per reading? Have you had any issues with plagiarism/piracy there?
I think this page will give you the info on payment:
https://kdp.amazon.com/en_US/help/topic/G201541130
So far none of my books have been pirated on Amazon itself, but it’s happened to others. Like Jenna Moreci on YouTube, for starters. ¯\_(ﭢ)_/¯
mm, i dunno. personally i’ve been moving in the opposite direction. i’m on wattpad but i cut the only story i was posting regularly. the only other site i keep up with is nanowrimo, and by site i mean the regional discord group.
actually, maybe that’s something you’d be interested in. you can join the nanowrimo site if you haven’t already and see if your geographic region has any discords or get-togethers. mine does bi-monthly write-ins, and online sprints and stuff. if your’s does something similar it might be what you need as far as accountability and encouragement goes.
other than that, if you’re looking for a writing/accountability buddy, then you could try posting an r4r or critque swap ad here on wacky. traffic here seems kind of low but it won’t hurt to try anyways.
You know me. I’m the Wattpad girlie.
I just like it because of the looks 
Also don’t get spam. Sometimes get reads. It’s peaceful. And it feels nice to post something on there and see it there.
I also happen to know two very good book clubs on Wattpad that I could join back at any time that really help me get feedback on my writing. Right now, I don’t have the time to join because I’m furiously editing.
Btw, you are right to say there’s practically nothing when it comes to sharing writing.
It’s hard for smaller companies to maintain with all the security they have to keep up, all the users they have to accommodate for, and all the marketing they have to do to get users, and they have to make money somehow, so they gotta do merch stuff… A single person cannot run a sharing-story type writing website. It has to be a big company willing to invest, or a niche with a large fanbase willing to pay.
I think it’s really hard to maintain a site that listens to all our sharing-story site wishes because a sharing-story site is a weird thing. Who is it made for? Writers or readers? If both, how do you satisfy them without losing all the money?