Oof, good luck. That's a hard decision.
Our daycare is doing kind of the same thing - they've stayed open for kids of essential workers, with everyone else paying 50% tuition to hold their place/keep the daycare open. They've recently opened for everyone again, and starting in June everyone is back to paying full price or un-enrolling. There are a few other centers that have closed, so they apparently have a lot of people asking about open spots.
We're lucky enough to both be able to WFH enough to cover child care, and to have not lost any income, and I think we're planning to keep both of our kids (1 and 4) home until I have to go back to the office full time. Ostensibly it's because it will make it easier on the daycare, because social distancing with toddlers is a joke, but also because I'm nervous about sending them back. They haven't seen anyone but our neighbors across the fence in almost 2 months, and I'm honestly scared to just throw them back into the petri dish that is daycare. I mean, I'd love to have, like, and hour to myself during the day that wasn't childcare or work, but a lot of people are in that position.
If what you're doing is really unsustainable for you, though, it's probably worth it to send them back. Could you maybe do half days, and try to shift your schedule around that? It would give you a little bit of a break, and still keep their exposure to other people lower than full time.