If you want to have a very low cadence - rather go into the Enviolo app on your phone and while you are riding and move the cadence slider down to 50rpm (from memory it goes down to 50) - I have found when riding very slowly through crowds of walkers that this cadence level works very well as you are not "spinning" your pedals and have better control over riding around people with a relaxed slow ride. Obviously your power level is set to ECO as well - or you could just switch off your Mission Control and use your Enviolo setting.As a note, adjusting to the Slowest setting has not helped in the past.
I agree with Stefan that the optimal rider cadence is around 70 rpm but in the above example you are not wanting to exercise your legs - you want a slow relaxed and controlled ride to manage riding in a busy pedestrian environment (on the beach front )