so I should change css path now or it's ok if it stays like futureforward/silverstripe-atlantis:css/admin.css

And the exposed files should be in public/resources/vendor/futureforward/silverstripe-atlantis

It should be vendor/futureforward/silverstripe-atlantis

it's not silverstripe-atlantis anymore

ok it's in vendor but under futureforward, didn't know it will put it there

Can you post the project and module composer.json files?