To be honest I have not written code for a widget since circa Android 4!
I am just looking at a project, testing on a big screen Samsung S9+ and having difficulty in getting the widget anything larger than 4x5 units on the screen.
The guidance on the forum is very old now.
Q. What is the relashionship between parent panel size and widget size on larger devices?
Q. Is it still appropriate to use layout scripts to size the panel + other elements?
Judging by the selection of native Samsung and other installed widgets I should be able to achieve at least 5x5 size. My guess is that a full screen widget would be 5x7 at standard icon size. The screen pixels are big at 1440 x 2960 but I don't see why this should not be handled just the same as smaller px screens.