I recently started posting on tiktok with a long dormant account and got similar results with videos so I started a bit of cursory research and this is the best I could come up with.
-The algorithm is currently prioritizing the following; carousel posts, going live, tutorials, well structured stories and longer form videos.
-The threshold for pushing out a post is higher than it was. Completion rate, dwell time, total watch time, saves and shares, follows are all more heavily weighted than likes.
-Poor performance from an initial seed audience will kill post reach very quickly.
-Posting more frequently won't help you but improving the quality(whatever that means) of your posts will or might.
-If you are getting 0 views on videos as a new account then the algorithm already has enough data to know or guess at least your video probably isn't going to do that well so it just won't distribute it.
I have an art account and was able to get way more views/reach/follows once I started posting carousel posts so for me personally the carousel posts are working.
You are probably going to have to make longer videos that have a pretty well thought out opening to capture attention very quickly or just structure whatever you are doing to fit into a carousel post.
I can only say what I have experienced anecdotally, I don't have full confirmation that everything I'm telling you is accurate but it does fit in with my own personal experience. I just did a lot of reading up on this.
I can't really tell you how applicable this would be to your situation.