How to use anchors for responsive UI layout?

Question

Unity

Please tell me what I'm doing wrong.
There is a Canvas on the stage with the following settings:

There are several panels inside the Canvas, incl. Panel with the following settings:

Inside the panel, there are 10 Buttons horizontally with the following settings:

The problem is that I can't get this panel with buttons to dynamically adjust its size to fit the screen settings, and when I change the resolution, it either gets cut off or disappears.
Yesterday I experimented all evening, looked at several tutorials on adaptive layout - it seems clear, I repeat the same thing, but it doesn’t work for me.
I tried a bunch of combinations of anchors, nothing helps ... How to set it up correctly so that the size changes to the screen resolution?