If the output is still comma separated, then replace text did not work. The solution above is how you do it. You may need to experiment with other replacements. For example maybe \t instead of [tab]. Again, the method above is what you need.
Here is a similar post that includes some of the other forms of "tab"...
I understand you are not able to figure out the exact ReplaceText syntax that you need. I have quickly created a flow and validated the following works as demonstrated. I had to use \t to match your string:
The regex you need is:
Table formatting is something entirely different and is not part of "csv" parsing....