booking through OTA is ok. I did this myself and can confirm that I received double XP for OTA-bookings, however given the uncertainty during these times, I personally would only book through OTA when the departure is within one week and I'm sure that I will use these flights. When you want to change the booking or have to deal with cancellations, OTAs will likely be a horrible experience.
I used the multi-city search on AF.com to force some 2-stop connections, such as looking for MXP-CDG, CDG-KRK (which shows me the 1-stop option CDG-AMS-KRK), KRK-CDG, CDG-MXP.