Premiere Pro 26.3 issues with transcription/freezing

Two issues that seem connected. Transcription tool usually works the first time in an edit session, but after a period (5-30mins or so) it stops working - it gets stuck in limbo saying “creating auto transcription” without progressing.

At which point premiere usually stops working entirely. ie unable to load clips, play timeline etc. Saving the project is possible though. Upon rebooting the app, everything works fine for a period, including transcription, then the same thing inevitably happens. 

The freezing also occasionally happens without even using the transcription tool. 

I’ve tried many suggestions on multiple forums (eg clear media cache, revert to saved layout etc etc).

Also tried going back to previous premiere version as this issue only started happening recently. nothing has helped so far.

Working on an M4 macbook pro with plenty of RAM, using external drive for media.