No such shortcut exists for anything other than Alt/Option + p for a Position keyframe, m for a Mask, t for Opacity, s for Scale, r for Rotation, and l for Audio levels. I don't think I missed any. Turning on the stopwatch for any property sets the first keyframe. After that, changing any property value sets a new keyframe.
I need that for the START/END properties of text layers.... or trim paths, or anything other that the transform properties. I want to be able to click on a property and just press a button and "keyframe" away.
Click on the stopwatch for any property and you are animating. Alt/Option + [ or ] will set an in point or an out point for a layer at the CTI. The timeline search feature will find start or end for trim paths on multiple layers at the same time. There are lots of shortcuts in the user guide. If you want to animate a shape layer trim path you have to navigate to that property in the timeline and then click on the property's stopwatch. I'm having a hard time figuring out how pressing a keyboard shortcut would save any more time unless you had a shortcut for every possible property on a layer.
You can explore the keyboard editor and assign shortcuts to a lot of properties. I don't know if trim paths start or end are included.