Dynamic "Wait" equivalent in keyword?

Any method that is on an onscreen object can be called in a keyword test.  So, you can use WaitProperty, WaitChild, WaitAliasChild, etc., in a keyword test by simply using the "On screen action" operation.

You can also, as parameters of any operation, use a "Code Expression"  where you can write a script expression to be executed... again, using such things as WaitChild, etc.

You can even "Run Code Snippet" as an operation in keyword tests to execute an expression outside of any other action.

And finally, if there is particular detection or functionality that you know you can do in script but can't figure out in Keyword tests.... you can write a script routine and use "Run Script Routine" in a Keyword test to execute particular logic and such.

In our projects... we use all of the above, depending upon the specific need.