Use what suits the thing you're training for, so hill climbing or grinding away off road the small ring would be more suited, whereas the extra flywheel momentum when using the big ring would be better for flatland crits or time trials
It’s extreme, but I have my tt bike on the turbo so 56T at the front, middle at the back. Lots of speed on the flywheel so you can have little micro rests without it spinning down.
Did a few workouts on my partner’s bike in the 34t ring and it felt much harder.
Use what suits the thing you're training for, so hill climbing or grinding away off road the small ring would be more suited, whereas the extra flywheel momentum when using the big ring would be better for flatland crits or time trials