How to place text on sheet of paper in video when camera move keeps hiding parts of it

I have a short video (under 5 seconds) with a piece of paper (I'm guessing A4 size) on a desk (the paper is stationary throughout, but the camera moves) that I need to place text on (though I'm supposed to place text on it, I think I may also be able to just replace the paper with an entirely digital version).

The paper has 9 drawn tracking markers on it (but they don't look very good - though they look like they're supposed to be evenly spaced, they don't really look like they are - they don't look measured/drawn accurately),

The problem is the camera moves (eg. up, and at one point only 1 tracking marker on the paper and 2 corners of the (A4?) paper are visible). Also something in the foreground keeps covering some of the tracking markers. I tried using the corner pin effect and manually keyframing it to place a digital paper onto the video, guessing at where the 4 corners of the paper were when some of the corners weren't in the frame (I also tried just placing the text, without the paper). The problem is, because the 2 lower corners of the paper are often not in the frame, the guessing at where they would be in the frames means it isn't placed accurately and so the placement moves around unrealistically.

Is there any good way of achieving this (maybe using 3D tracking and placement?)?