Considering your specific goal, do nothing – you are solving an XY problem.
I could post an answer on how to turn it off, but based on the background you shared, I decided to give a different answer.
As you shared in comments, you already have an exception added into Windows Defender which allows your software to work as expected. In your question you did not indicate any performance or compatibility or other issues which in some corner cases can be reason for disabling the protection tool completely.
To address only your specific blocking issues, you have found the proper solution. This is the purpose of exception lists in threat-prevention software and you used it in the right way. You gave no reason why it is necessary to disable the entire protection instead of adding just one exception.
Any weakening of security of your computer is generally only worse. Do not switch off Windows Defender if the problem has a valid working solution (for example, using the exception list).
Alternatively you can replace Windows Defender with other protective software, e.g. with an antivirus program or security suite. (They will turn off Windows Defender, too.) But it may happen that they will cause a conflict with your application, too, and you will end up adding a new item into the exception lists as you did it for Windows Defender.
UPDATE regarding current voting +15/-12:
Based on the comments, it is possible that guidelines for answering are not in common knowledge of many users of this site. Answers pointing to problem found in the question, replying with "don't do that" and proposing another solution are perfectly legitimate. I understand some users are landing at this question when emotionally charged against the Defender, but based on the above, please think twice before voting down. Happy knowledge sharing!