You've got to be tweaking. Nobody is that pathological naturally.

G53 does not trash the work offset. It has no negative affect. As you can see in this video the displayed work offset coordinates remain accurate through out. It does not cause a problem.

https://www.youtube.com/watch?v=c9rFFYyTUkE

You are just full of ****, and the fact remain a G53 safe Z height move is safer than an arbitrary G0 move because you don't have to check that it will be safe. If it was safe last time it will be safe next time and every time. Undercutting not withstanding of course.

If you wanted to be "safer" you could save the current coordinates to variables, and then return to them after executing your tool change, but if you are only doing a safe z move to implement your tool change its not necessary. Still that assumes the machine behaves as does the virtual one in my video clip.

Other problem? You mean where he had 2 T(x) values. You already corrected that. Not helping... maybe not helping you, but you can't be helped and your own words betray you.