professional athlete

It's not that simple. You may need a written authorisation from the game producer, depending on the game. Otherwise, Youtube may not enable monetization for your videos.

 

I think it's possible but not easy. You need to differentiate from everyone else to get more chances. To go pro at something means that you need to study the subject, become an expert, an authority.

 

Federico and 111kg are correct. You have to be good at it, but you also have to have the right permissions to promote what you're doing. You should be ok as long as you're doing it through the company and have permission to or are doing promotions that are within their guidelines for how they want to advertise their product or service that you're placing out there and are doing what's beneficial for them.

Initially I thought you were trying to do something else; I was talking to someone on the phone while responding, so I partially misread your approach and what you were wanting to do. You can make money promoting and reviewing products. People do this all the time and make decent money doing that. The more popular you are and the better the results, the more you can command in rates for what you do.

As long as you were hired by the company or they have no misgivings about you promoting them in your own way, you can do it but you would have to get your foot in the door either with them as an employee for that, or the more accepted direction of doing that as an independent contractor. It's not out of reach, but like anything else it requires work still. You'd have to build it up, be patient with it, and have a way to sustain yourself while you do that on the side until it can be your main living.

For the sports and gladiator side of it, you'd have to be in pretty good shape and have acting skills too if you're going to be live or recording it for videos online. The entertainment draws people in, and the better you are at it the better the sales translations usually are. You'd have to love to do this and really want to put forth your all. Even starting out, even if you only do it part time, you'd have to devote full-time effort and planning to pull it off.

 

I agree with what the other posters have already said. It's not that simple. You really have to give your full attention to it. Being a professional athlete is a real deal. You cannot become an expert in something overnight. It would take a lot of time and effort on your end.