Slow load of jupyterlab

We use 3.1.4 version of jupyterlab with enterprise gateway. For contents manager, we use S3. I am trying to debug the slow load of jupyterlab and on initial analysis, i see nbconvert taking a lot of time

Any pointers on why nbconvert is taking a lot of time? and what could be causing this delay. Is it related to using S3 contents manager or using enterprise gateway. Where should i be focusing on to debug this delay?