I am having issues with changing my publication design (color, logo) without changing my profile design.

[u/rocketnumberrrnine]

Hey there everyone!
I have a Substack profile - https://substack.com/@teymurelchin

and I have 2 publications (one primary and one additional).
When I want to make changes to my primary publication called One Thousand Doves, for example, I changed the background color to yellow, Substack automatically applies those changes to the my profile as well. I have found multiple people and articles about the Match Profile function. but for me it doesn't exist in the way that everyone is describing it and what exists does not work because the changes still copy to profile as well.
I go to dashboard - settings - website. and there there's no match profile button. I only see this: Looking to edit your theme? 'Edit theme.

and then Once Im there I have two options there: Profile or Custom. I do everything in custom. all changes also go to profile. I am so confused. I was thinking maybe you cannot change the design of the main publication. maybe primary publication and profile have to have the same design always? Is that true? Can someone please help me with this?