Hello Phil.
There i a bug on the function of "UART_DRV_IRQHandler" , please add the two line to the
receive interrupt and send interrupt :

you can also refer to here :
The usage of UART callback function install
After fixed here , if your project still can not work well , please send you project to me .
Have a great day,
Alice Yang
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------