You can fix this, but you have to carefully layout your UI (using Control Nodes) and also make sure you have to correct screen settings to different monitors will get the right resolution (depends on the look you are going for). Check this:
https://docs.godotengine.org/en/stable/tutorials/viewports/multiple_resolutions.html
Then make the UI inside containers, for example make the top Node a CenterContainer, then add a VBoxContainer and then put the text boxes inside that. You might need the top most Node to be a Control and then set the rect size to the full size of the screen, there may be an automatic way to do this.