Khurram Aziz you can't shrink the connection bar into a smaller size because the dimensions of the connection bar in both the Hyper-V client and the Remote Desktop client are hardcoded by Microsoft and scale automatically based on your Windows 11 system display resolution and DPI scaling settings. There is no configuration file or registry key that allows you to independently make the bar smaller.
And you also can't move the connection bar to the left or right vertical sides of the tablet screen to act as a side button. In the native Hyper-V client, the bar is permanently locked to the top-center of your screen. However, if you switch to using the Remote Desktop Connection client as previously recommended, you do gain the ability to click and drag the connection bar horizontally. While you still cannot move it to the sides of the screen, you can slide the bar far into the top-left or top-right corners of the top edge to get it away from the center buttons of your application.
If sliding the bar to a top corner in Remote Desktop is still too intrusive for your tablet workflow, completely disabling the bar's visibility through the Remote Desktop Display options remains the only official, built-in solution to achieve a completely clear screen...