In a fit of unwarranted optimism, I started something I call "Night School" on Reddit, which is basically a series of short writing exercises (max 500 words), released weekly, each designed to focus on a different technical aspect of writing, with guaranteed critique from me as long as it meets the lesson parameters. I did something similar a while back on Royal Road and forgot how much work it is to draft a personalized critique, especially when overenthusiastic new people decide to do all the lessons in rapid succession.
I haven't been advertising it very much because I've been avoiding the work, but if anyone would like to join me in coming up with the lessons and providing the critiques, I think it could become pretty damn popular because people crave feedback. It would be a pretty good platform to promote your own writing eventually, with mod bios.
Check it out and let me know if you're interested: https://www.reddit.com/r/WritingNightSchool/