join a UDF on a join with its parameters?

feasability of joining UDF parameters in a (cross) join?

what is missing in being able to join the parameters of the below udf with a derived table?

thanks-
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SELECT t.* FROM dbo.func_UDF (@UDTT, U.column1, U.column2, U.column3) AS t CROSS APPLY
(SELECT column1, column2, column3 FROM join and conditions) AS U

@UDTT is a user defined user table type with READONLY attribute.