Me too.
I’m not as bad but there’s a definite difference in comprehension.
I used to read upside down, and still do sometimes, but more for fun. The only advantage this has ever had is that I learned my IQ by reading papers on a guidance counselor’s desk.
I can also write in cursive (in English or Cyrillic; I’ll have to try Hebrew) with both hands simultaneously, with the right mirror image. It’s also pretty easy for me to write backward or upside down and backward. This has no value that I can discern. I suppose it will be entertaining after a stroke.