A Covid-19 Romance is one where it is temporary for at least one of the people. The person is removed from their usual habits and routines. They can't do their "real life". The person is lonely and casts around. They find someone who is also lonely. An acquaintance is expanded. It is deepened and becomes a friendship. Then it can move into a romance.
But wait. Covid-19 starts to let up. The person's usual habits and routines start to open up. They try to do it all. They are less available. The lover protests a little but tries to accommodate them and be patient.
The person says, "I need to get back to my real life."
And they are gone.