The spacing of every component feels wrong, the font choices are off, the text is too small, there is way too much white space, the "other video" section looks like its just jammed off to the side. The overall feel of the website is very amateurish.
When I go to https://joinpeertube.org, I'm met with a double hero section that tells me about PeerTube, which is ultimately meaningless to 99% of the population.
When I get to actual content on that page, it's not an aggregate of all of the most popular videos across the federation, it's a description of the types of videos you can find on federated sites with links to the sites and not video embeds. You're telling me on the front page that I have to do legwork to find the videos I want to watch. You're already not competitive. You already lose.
Creators go where users go. If you don't build the platform to attract users, you will not get the volume of content that is required to hold people's attention. There's a reason why people come to YouTube, Reddit, Hacker News, Reels, etc. There are almost no clicks between the user and the content, and the content is plentiful.
Every time I try to use PeerTube, I have to try to find where to find the videos. As someone who's been chronically online since 1995, it's not that big of a deal. I can find them eventually. But that UX sucks, even for me, so it's probably utterly untenable for the vast majority of casual users.
You are trying to compete with slot machines by inventing a machine that makes the user read a bunch of stuff between each pull of the lever. It's not super difficult to see why that is a competitive disadvantage.
But, boy, I do know this: when I sit down, I better be able to just pull the lever and start.
You say that you're genuinely interested, but chances are that any given maintainer is not. Willingness to actually listen to UI/UX critique is what separates the Blenders from the GIMPs.