I'm sorry, but there is no way to do this. All usernames are generated as <a> html tag, they don't have specific classes to be found and disabled by JS.

@robert Because this is for all users when user click on his own username. When click on any other user username, opens UM profile page, Yes. BUT when user click on his own username then the UM profile does not open. I want the UM profile to open even when user click on his own username.

Ok, you should always provide detailed information of the problem. Now it's clear, and I'm really sorry I don't have a solution for you. This is a site specific bug. There is no such problem on other wpForo/UM websites, so it's very hard to find the problem maker. There is some conflict point and ti should be investigated directly on your website. You should contact us via supportgvectors.com email address and send admin login details. We'll find time within a few days and check your website.

In video I just try show you difference between click on other username and click on their own usernames. Other - UM profile. Their own - Forum profile. But I want UM profile on their own too.

Example:

I login with Test123 user...
When I click on any other username (SelfijuBums or Millenium etc.) - UM profile.

When I click on my own Test123 username - Forum profile.. not UM profile.

I want UM profile when user click on his own username.. just like clicking on other usernames.

Hmm... I see you click users username, and you go to UM profile page, why you say this is for all users? Don't you want to open the UM profile page when you click the usernames?

Maybe is possible create non-clickable usernames??

Ok, thank you for the video. This issue only exists for your user, it should work for all other users. I think this is a bug and we'll try to fix it in the near future.

When I click on other profiles, SelfijuBums and Millenium, opens site profile. This is what i want. But when i click on my own profile Test123, opens forum profile not site profile. I try this from other devices but when i click on own username, opens forum profile not site profile.

To Dashboard > Forums > Settings > Features Tab "Profile Page" option I HAVE Ultimate Member, but still opens forum profile, not site (ultimate member) profile.

This should work fine. I think this is a cache issue. Please go to Dashboard > Forums > Dashboard and click the following buttons:

1. Delete User Cache
2. Delete All Caches

If you have cache plugins, then purge all kind of caches and exclude the forum page from your cache plugin: https://wpforo.com/community/faq/wpforo-and-cache-plugins/

Also, please check all users usernames, make sure this is not a user specific issue. And let me know where exactly you click and what forum page you are on.