@ Zerosquare - Thanks, I didn't knew before that reading WORDs from odd adresses is not possible.
@ HPMAN - Thank you for your advices, I think I need to dive deeper into that USER_subroutine stuff.
And yes, indeed I was thinking about a spinner to control the paddle but that is unfortunately far beyond my hardware skills

I have found Razoola's article on the Wiki (
https://wiki.neogeodev.org/index.php?title=USER_subroutine)
and his video on YouTube: