Seconding @Kenn2018's recommendation, I think you'll really enjoy our Seasons of the Ukulele forum. This is a weekly, themed song challenge, and there are quite a few folks submitting originals every week. There's also a subforum there for videos that are too late for a week's theme, or altogether unthemed. This has been going for nearly 12 years (currently in our 618th "season"!), so as you browse past seasons, you can find thousands of videos that our members have posted over the years, with every level of performance and production skill you can imagine. It's a welcoming, inspiring community-within-a-community, and one of my favorite things anywhere on the internet.
And if you're interested in posting videos outside of friendly competition, we've got a video forum, cleverly entitled Videos and links, where lots of other members are posting their performances.