DH and I were just discussing our food options for the next week. We have no problems in getting what we need (SW London) - supermarkets well stocked around here and we are very flexible about when we can shop.
Just checked and the usual Easter Sunday closure is on the timetables of all our local stores. It’s an anomaly, a concession given to the anti campaign in the 80s, when Sunday opening was first allowed. The reason given was that staff and customers would be able to go to church on an important day in the religious calendar.
Not religious myself, and not bringing this up as a general discussion point, but at this time I think an exception could be considered. It is going to increase the number of people who are still working a traditional week, either from home or physically there , having to do their shopping on Friday or Saturday. The queues on those days will be proportionately longer. Stores have taken on a lot of new staff, on flexible contracts, so could surely cover the hours.