How to remove the flush mount ceiling fixture
I don't think the "bulb" can be replaced as it doesn't contain a bulb. This fixture is only 1" deep. It most likely has a hardwired LEDs. I looked at the specs for this fixture at the link you provided and also downloaded and viewed the PDF specs. There's nothing mentioned about bulb replacement. I installed a similar fixture several weeks ago. The diffuser "globe" is what you should be trying to remove, not the trim ring.