In the Literature forum, for example. I want to share my story with the community, but there is a limit of only 10000 characters per post. If publishing own stories in a literary forum is against the rules, then forget about allowing more characters until someone else will find another reason. But can you at least make it so HTML code will work in order to edit posts? (Not sure if this is how to call it)

I saw in the "Changes in the Pipeline" that the html thing was adressed, but what i meant were stuff like [b][/b], [spoiler][/spoiler] and so on...

Instead of uploading to google drive, can i make it simplet and provide a link to my site? Though it would feel more personal if I could post my story here...

There are no plans for BBCodes as far as I know. There is no technical logic reason for limiting the size of a topic as long as it gets sanitized. Ultra long replies could collapse to a standardized reply height when a specific soft limit has been exceeded.

Since publishing content to a forum is kind of open sourcing it, you may consider to use GitBook. Take a look https://www.gitbook.com

You don't want HTML. You want a way to use bold or italic and links and lists and stuff like that. We already got that (not 100% working at the moment AFAIK)

The forum already uses Markdown: See https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet