Amazon photos/Apple photos


I am brand new here and impressed with the information I am finding. I am putting this question in uncateforized but if a moderator thinks it should be in Apple please move it. Thank you. I have searched everywhere including the Amazon site and other internet searches. After switching to an iPad Pro exclusively, I needed a backup option that was not an external drive. After much research I ended up with Amazon photos as it keeps the originals. I have about 35,000 photos I seamlessly transferred. I used the automatic tranfer option. Can you imagine manually doing that? Anyway, I then realized it works like Apple iCloud and my deleting is synced. I want everything on the Amazon drive to be permanent unless I choose to delete it manaully. My assumption is to just change the option to manual but I am afraid that will change the whole process and start it over again, or horrors, delete what is on my iCloud.
If anyone knows for sure and has experience with this I would be most thankful.