Hello @fpageot ! I’m a fellow Enketo user - also with large forms and repeat groups - and agree performance can sometimes be very slow. It seems that there have recently been a major change to Enketo that should improve performance a lot - see Huge leap in performance - however these changes haven’t yet been fully applied to KoBo systems, so the Enketo performance improvements aren’t available to us yet. There were some Enketo changes applied to KoBo in December but they were rolled back and I’m not sure of timings for them to be integrated again.
However in the meanwhile it might be worth going through the items listed in the Enketo blog above to see if you could work around any of the known performance hits? e.g. turn large select lists into external selects?
Go well, Nat