I am in a similar situation. Outbound (U.S. to Europe) booked with AA, return booked with Flying Blue points on AF. The outbound is not an issue as I can cancel without penalty due to AA's current COVID policy. For the return, Flying Blue charges 50 EUR per person to cancel and re-deposit the miles. I suppose there is a fee waiver if the actual flight itself is cancelled. My trip is not until August, so I have a tiny hope of still making the trip. For the OP, I would just wait until a few days before your return and hope your flight is cancelled and you can redeposit the miles without penalty. If flight not cancelled, pay the fee.