@Tomato, I should mention that I already provided them a video, voluntarily, showing my app on my watch via screen sharing. So the fact they demand more is a sign of a "shark strategy". They feel my desire to comply ("blood") and attack with endless requirements. If I agree they'd demand another video with different equipment, and so on and so forth.
Another problem is fully practical. The video requires Apple Watch + equipment (e.g. Mac Book) + camera. I simply can't do it in a good enough quality with my two hands. I need to hire a professional for that which is hard for an Individual Developer. Much easier would be reject and reapply hoping for a different reviewer.
And finally I would note that I have competitors who perform worse than HeartBLE and I doubt any of them was forced to make a video.
The real problem which blows their mind is the monetization. I selected the "XX-day Trial" + non-consumable model. Just wanted to give it a try, get some experience. Turns out reviewers hate it (or simply not familiar with their own guidelines). Every and each time they somehow condemn my IAPs, which I never expected during the development. I though everything is simple and obvious, user has to tap one button. Also, every time I provide them with credentials to test my IAPs and they never use them.
I guess the problem is deeper than me "not wiggling my tail" and not showing desire to do anything they demand. Maybe they hired cheap and incompetent people to save resources, or maybe it's a special "killer team" that always rejects no matter which app gets to them. I'm submitting apps since 2014, I worked in companies that build literal spam and never struggled with review like today.