Do you have /ac "Sheltron" listed multiple times in your macro? The more rows of that you have, the greater your queue window will be. With a macro like that, you shouldn't need to mash the button (in fact, mashing the button will make a macro like that perform worse) provided that you are accustomed to the rhythm of when your animation lock lifts. But if you're less in-tune with the proper timing, then non-macros can be really helpful because of their larger queue window.
Yeah /wait macros are a whole can of worms. There are certainly use cases for them where they can be helpful, but most of the ways we as players would like to use them don't work great due to the limitation you mentioned!