— The app is not optimized for mobile devices.
— Overall performance is poor.
— The design does not comply with the guidelines.
— The app is slow when filtering, scrolling and scaling the graphs. 
— The graphs take the entire width of the page when viewed from desktop browsers.

The design for buttons and timeline (navigator) elements has not been updated for stage 2

tooltip position

UI scale is not depended on device pixels, so it is too large. I have a laptop with Full HD display, but only 13 inch in diagonal, so I put 150% scale in my Windows settings to scale all UI.
I advice you to use window.devicePixelRatio, when you operate with pixels in JS. There is an attached screenshot of how it looks on my laptop.

However, maybe it is not right and the reason of it is another, but this is my opinion.

Administrators Telegram, where my graphics? Yesterday I sent a zip archive, but I do not see my work in the list

Baloon covers a huge part of chart, so you can't see a part next to current point.

There is no "Title" tag.

In Edge the lines can become a bit ugly when selecting smaller range of dates. But that doesn't break the core functionality.

The resizing of the timeline (navigator) magnifier can lead to disappearing of the elements in the preview when going to far on the right. It doesn't happen on the right side though.

And I like that the drag-to-resize left and right blocks can switch positions. I think that is a useful feature.

Overall I don't think that this work deserves so many dislikes.