You can use the formula tool to solve this. Use the formula tool and write conditional (if-else statement)
e.g.
1) If characteristics_crm contains number then characteristics value = characteristics_crm else retain the value of charecteristics_value
2) If characteristics_value contains string then characteristics_crm = characteristics_value else retain the value of charecteristics_value
Hope this helps.
If yes, then please give me a star to appreciate my time and efforts.
If not, then please upload a sample workflow with text input and your expected output (manually created) so that I can work on the same.