I think I've fixed it. Worked out what the issue was.
There's a new toggle for community supporters which gives easy access to switching between light and dark mode. It looks like this (the light bulb on the right). Just hit that and it toggles between the two modes.
If I hadn't seen this post, I would never have realized, but I think the system is seeing me incorrectly as a community supporter. I have the light bulb toggle and I didn't even notice the banner adds are no longer present. Not sure if I'm the only one affected this way or when the change happened.