Farkarava, Rangiroa or both?

We plan to spend a week end Oct. on one of these atolls for snorkeling from the beach, diving (we have over 150 dives) and getting to know island life a bit. We enjoy cooking and plan to stay at a family run lodge (not a resort). Which island would you put first and for which reason? Which booking platform would you choose? Some places only provide a phone number in google maps, which messaging app is commonly used? Thanks for sharing your thoughts and recommendations!

Edit: do you by chance know if there is a reef restoration project on Rangiroa that may be interested in volunteering work? There seems to be one on Morea. It appears that they are often connect to very expensive resorts (great source of Fundraising), which we are not really interested in… (Not sure if this is the best way to post the question on Reddit )