How to create/simulate a modeless form in VSTA?

How do i create a c# windows form/UserForm in VSTA that behaves like a modeless form in VBA? If i include an input textbox, only characters that are not assigned as shortcuts are able to be typed into the TextBox. CorelDRAW still seems to maintain the focus.

I am using Visual Studio 2019 Community edition and new to both VSTA and c#. Any detailed guidance would be greatly appreciated.