I agree on the last point. I've even written directly on it, imagining what it would be like to be the supreme being. I think God would sooner go mad than be bored.

I'm not sure you quite grasp Kant's transcendental idealism. He doesn't say there's no such thing as knowledge. It's a question of how knowledge should be philosophically interpreted, and what exactly is the object of our knowledge.

The principle is somewhat self-denying in that it makes all knowledge partly subjective in reflecting the cognitive tools we bring to bear. I've written about this in the first three links below.

https://medium.com/original-philosophy/how-understanding-the-facts-makes-all-knowledge-partly-subjective-bda98e29f990?sk=387e9e50b01927fbaae66014e5ed731a

https://medium.com/original-philosophy/why-we-should-reject-the-conceit-of-objective-truth-c3b3195a883c?sk=f2cefc17e62b7737e31c4523775fc9ed

https://medium.com/the-apeiron-blog/what-is-the-nature-of-ultimate-knowledge-664642cf8147?sk=73f128be23b11ea1e09a8c3e83db51ed

https://theapeiron.co.uk/the-gall-of-imagining-gods-reality-2bfefcdd475?sk=3dc4e65181ef627a6ef84d57731097ae

https://medium.com/the-philosophers-stone/tyranny-and-the-horror-of-being-god-3a77f319ca77?sk=441d211f36d0127ccbf6bfbd94fe1771