I haven't used Dynamousewheelbind, but if I understand what it is correctly, it's for binding to mousewheel events rather than middle and right mouse buttons as the OP asked about.

Also, mousewheel events are slightly different on macOS aqua; they don't use buttons 4 or 5 as X11 does, and they are scaled differently. (Both are things I addressed in Tcl::pTk 0.93.)