I'll reiterate it again for you

If airlines felt 90 minutes was too short an MCT from T4 to T3 they would increase it and NOT offer connections of 90 minutes.

It is not in their interest to offer unrealistic connection times - too many unhappy passengers and possibly too much EU261 compensation to pay out.

Hundreds if not thousands of people day in day out, week in week out, month in month out, year in year out do this connection without issue.