Hi KNIME Developer
For the data type conversion for any type of file which solution is already available .
(Hint: create node using Sql script into graphical interface and also can generate graphical interface to sql script as Alteryx developed)
Instead of fixing your KNIME node for many years, You can simply look at the Alteryx node (select node) how they developed as solution is already out there.
I am using alteryx to convert any kind of data type conversion and it works well for database or any file etc
and it is very easy to change data type with table column in configuration window.
I suggest you to look at altryx product as reference how they can develop/configure it.
Please have a look at the screenshot as reference how alteryx developed well and KNIME can develop something similar
with Alteryx configuration then many people will use KNIME products.
Hope it will help to improve KNIME product