I wonder though if by the time OP flies, (some) lounges might already be open again. I know LHG is bleeding money right now, so they'll try to cut all non-essential costs, but if they're slowly rebooting their flight network starting June 1, demand for lounges should also come back up. Maybe that's just wishful thinking though, since I'll be transiting FRA on June 7 myself (albeit only for 1:40h, so it's not too bad after all).