Interestingly, for this month of July my local audax club is trying to start doing BRMs again -- more specifically, BRM400 and BRM600 at the end of the month. But to comply with the current local restrictions, almost everything is do-it-yourself. "Collect the brevet cards on your own, there will be no one at the checkpoints so find a shop to stamp it for you (or get a receipt), send a photo of the brevet card via phone once you complete the ride."
The 600k route looks relatively easy, practically can be considered pancake flat. I guess it's to ease people back in since there will be a lot of randonneurs who are no longer in peak form compared to the Before Times (I'm probably not too, since the most I've done is a 200k). If there's decent amount of participation I guess I'll join as well.