
When you upload a file with this name already exists, SharePoint will let you choose replace the existing file or keep both two files, it is by design. Until now, there is no option to change it.
Thanks for your thoughts and suggestions on the product.
We suggest that you can go to the Microsoft Tech Community to submit a feedback.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.