I don't have a Tranzport, but reading your post it looks like it's ruled out for me.
CTRL-numpad2 and numpad1 are the two keystrokes I use most often.

For me it might be more beneficial to just have a generic way to remap shortcut keys to custom ones. The ones provided seem to be shoehorned in over time and don't always follow function or layout .

Essentially abandon the provided shortcut keys provided, and use my own. A nice simple mapping file would do it.

Same for custom midi mapping.