You are welcome.
Breakpoints are not just for pages, but also individual elements on that page, or even inside any assets, like headers and footers. For example, I had very busy page, and everything but this cluster of circles needed more control over their placement. I gave that “container” which held them, 5 breakpoint control, while the rest of the page utilized the three by default. So, even on the deskop those circles in the cluster relocated/shifted position.
Since breakpoints deal with width, you must rely on design and the inspector to control the heights of the components of the page. For example, instead of using fixed pixels or even percentages, vertical heights is one of my favorite tools.
So, if you need the viewport to fill the screen of the desktop, tablet and mobile devices, you utilize the 100vh to cover the top to bottom effect. I use this often for artists and photographer sites. This dimension has nothing to do with your breakpoints.
This is what I love about EditorX and. some others are doing with respect to height/width responsive desiign.
Perhaps you could show me one of your issues and I could try to assist you with a solution.
Sometimes, it is the design that is the culprit to poor performance, which I have been guilty of often.