I've purchased the game from the official Minecraft website and and signed in on the Minecraft launcher yet instead of letting me play the full version it says buy set Minecraft java edition or play demo and I've completed the setup wizard thirteen times to no luck
This report appears to be a duplicate of MCL-16570, which was later resolved as invalid, because this is an account issue and the bug tracker is unable to help you, as the team does not have access to the appropriate resources. Please see the Mojang Studios note attached to the parent ticket, to potentially fix this issue.