Will the publisher of religious content be rewarded and receive blessings for their posts even if no one interacts with them?

Spreading good is a righteous deed for which its doer will be rewarded, as Allah says: "And whatever good they do, never will it be denied to them," and His saying: "And if you obey Allah and His Messenger, He will not deprive you of anything of your deeds." So continue spreading good and inviting to it, and have a good opinion of your Lord.