Don’t be sorry for asking questions, these are points I need better documentation on so it helps to ask.
After running “Check Level Hot 5x5.gcode” did you mark down on paper which points need adjusting?
You need to individually adjust those point either using “M421 InJn Qz” commands in the console input or creating a macro that adjusts all of them in one pass. Then you do another M420V command to get the new matrix values. Those go into the second matrix on the Google Sheet. You could, like you suggested, make a copy of the 1st matrix into the second and make adjustments to it there. The TWEAK matrix just gives you a difference between the two that is useful to run after doing steps 1-4 as you stated on future times.
What I really want to do is create my own manual level with Gcode to run after steps 1-4 of your list. OR, if Snapmaker would just lets us do the level with the bed heat on it might negate the need for all this complexity.