[Scott Lee]

Transcriptive 2 for Premiere Pro has that functionality, and for simply syncing audio with existing transcript, there’s no additional charge for API use. The product itself is rather pricey, though. You might have already hit upon this or other solution to your problem. If you have found some other solution, please be kind and comment on this reply.

One of the things that makes me hesitant to purchase this product is the Adobe’s plan to integrate transcription feature into Premiere Pro in the near future, which may force the Transcriptive team to mark down the price of their product.

Anyhow, I’ve tried the trial version, and found it (the particular functionality you mentioned) marvellous.

https://aescripts.com/transcriptive/