Q: Could one have a liturgy where people brought their own unleavened bread to church that would be consecrated by the priest though held by the people of God?
A: No, that would not fulfill the image of the liturgy presented in the liturgical books. There is indeed an ancient custom for people to bring bread and wine, as noted right in GIRM 73. But the point is for the people to offer their gifts, not to hold onto them, and to receive communion, not to feed themselves.
Then there are other complications: How would the community supervise quality control? What if someone didn’t know how to bake unleavened bread? What about the sacred vessels that hold the elements? Why have a consecration of the sacrificial offerings completely apart from the altar?
The pandemic has caused people to think up a variety of ways to preserve hygiene, but they should also preserve eucharistic theology.