Dear Client,
I understood your migration of code and API extension in 2.3.4 for getting a product from API from your existing API to your new installed API.
I shall make the API that you want and performing the optimization of code, I am working since 2013 as a Magento developer.
I have migrated 40+ Magento 1 to Magento 2 and 10+ Magento 2 to higher Magento 2 with all functionality, features, extensions, and more.
Waiting for your positive response to a project.
Thanks,