If you take all your legal advice from people who repost whole movies onto youtube and put "no copyright intended" in the description as if it's a magic talisman, maybe.

But in the actual world, if you use someone else's trademark to make money, you're gonna have a bad time, and part of that bad time will be learning in excruciating detail what "public domain" and "fair use" actually mean.

"Something is viewable by the public on the internet" is not "public domain". Public domain means copyright has expired on the material, or that the material was for some reason never protected by copyright (such as certain works of the federal government, in the US). "Fair use" is a defense that can be raised to claims of copyright infringement, and uses a multi-factor test. None of the factors are "but it was there on the internet for me to take".

Neither of these involve trademarks, which are a different area entirely. Using someone else's trademark for your profit is very much not "public domain" and not "fair use", and will not end well.