Donating My Dads Logbooks Johnny "Timber" Wood
Paxing All Over The World
My father donated his wartime log books and medals to Hendon prior to his death. They gave him high quality PDF scan files on CD. So we have them for reference and family archive. My nephew became an ATPL and his wife arranged for the PDF files to be printed and bound as facsimiles.
Sorry but I can't help with long term storage advice. More than one copy sounds good and at least one of them on a cloud somewhere also sounds attractive depending on how much you have to store and the costs. I am sure there will be many articles about it.
Google - long term digital storage solutions
I skimmed these and they seem not-ridiculous
https://askleo.com/best-long-term-storage-media/
https://www.howtogeek.com/356473/how...ually-forever/