How long should TinyMPU6050.h calibration run for?
I feel so sorry about the previous releases of TinyMPU6050. I've just released v0.5.0 that shall soon be available at the Arduino Library Manager index.

The calibration method indeed was messy, so I decided to keep it simple. I also removed dependencies of String objects and Serial stuff and it seems to work pretty fine now.

If you keep having issues with that, please let me know!

The official link to release 0.5.0 follows:
https://github.com/gabriel-milan/TinyMPU6050/releases/tag/0.5.0