How to remove Advertisement brochure

As well as what Ged has told you, the beta version now has a Focus Mode option in preferences.

I only happened across this thread yesterday, and don't know for sure all that it does, but it sounds like it might cause Photoshop to have less distractions.

https://community.adobe.com/t5/photoshop-beta-discussions/new-beta-feature-focus-mode/td-p/15035538

Photoshop Beta now includes a new 'Technology Preview' called Focus Mode.

Focus mode limits the appearance of non-essential messages so that you can stay in the flow when using the program. With this new option enabled:

1. The Welcome screen will not include 'What's new' feature descriptions
2. The 'What's new' message will not appear when Photoshop is launched
3. Blue in-product alerts promoting discovery and use of certain features will be suppressed
4. The color mode preference will be auto set to 'neutral Color Mode'

To enable Focus Mode, start Photoshop, open Preferences, scroll down to the 'Technology Previews' section and check 'Enable Focus Mode'. Restart for changes to take effect.

@Harri Pietila try unchecking this option in the Creative Cloud preferences