If you're not collecting personally identifiable information, you are not affected by GDPR and can proceed as normal. Not exactly sure what "recording facts about the world" means, but if it doesn't involve individuals and their data, you don't have to change anything.
I agree that general information should be free, but there is a difference between general information and personal information. Personal information (like the photos I take in my bedroom) should not be free unless I agree to that.