I second 2.)
When using spacedesk viewer on an Iphone the size of the screen is already quite limited and the button (white rectangle with 3 lines) takes even more space away.
As is it doesn’t even add any new functionality as the only real option it provides, besides minimizing and closing the menu, is to disconnect the device, which is still possible and quicker by pinching the screen with two fingers. The button got introduced with Version 1.0.55 of the IOS Viewer App.
I would love to have the option to hide it via a toggle or something in the options menu.