Currently, only space templates can be promoted as per mentioned in the following documentation: Page Templates
It'll be great if we can promote Global Templates on space by space basis
Once you promote any blueprint, all global templates get hidden in "show more" area - with no ability to promote. Please allow a global template to be promoted per space.
At the moment I have to create a template for each space (copy of the global template) and then promote it inside the space. This creates unnecessary duplicates.