Thank you for investigating and sharing your resolution with the community!
Since Microsoft Q&A does not allow the question author to accept their own answer, I'm reposting your findings here so others can benefit, and you can mark this as the accepted solution.
Reposted on behalf of Zulkarnain Md Sabri:
"I have tried again this morning (my local time) and now, the window for 'New data product' has three sections, including a Custom attributes section after I clicked Next in the Business details step. In this new section, the Create button appeared and I was able to successfully create the data product. It seems the issue may have been resolved automatically - possibly due to a backend update by Microsoft around the time of the incident."
Thanks again for following up and documenting this! It’s very helpful for others encountering similar issues. If this resolves your query, please feel free to Accept the Answer so the community can easily locate the solution.
If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information.
If you have any other questions, please let me know. Thank you again for your time and patience throughout this issue.
Please don’t forget to Accept Answer and Yes for "was this answer helpful" wherever the information provided helps you, this can be beneficial to other community members