The "top downloads" pie chart is a little misleading, actually. The package manager itself doesn't have any visibility on package downloads because those are done through npm, and not nbbpm itself. What it does track is how many people ask nbbpm to suggest a version to download.
For example, if you run v1.8.1 and you want to download a plugin, the latest version might not be compatible, so the ACP will query nbbpm for a suggested version. That's counted as a "download" (since the "suggest" call is done behind the scenes and is opaque to the end user).
So you could be seeing true downloads... people downloading your plugins... or someone's just hammering GET /api/v1/suggest?package=nodebb-plugin-prometheus a lot 😄
Will offer my way of fixing.. probably something went wrong in the themes, aside from css, probably version mismatches with the core nodebb version your using. The below will revert to working vanilla and lavender theme versions that match w/ your core nodebb install version. (probably need to stick with whatever theme versions it reinstalls, because I've always had problems w/ updating themes, I don't upgrade them anymore) Stick with what came with the nodebb install originally. This will revert back to originals: