You are going to get hit by copyright infringement real hard if you upload videos with those music/soundtracks unless you buy the license for it (quite expensive, though some indie composers might give it to you for cheap).
I bet you didn't read what the OP has just posted, how can you be copyrighted if you're just listening to music? I didn't know that their listeners are just limited for those who pay
He's not making videos nor uploading with a random music on youtube, what he just did is that he shared the link from the youtube, how can you be a violator for that?
The best thing you can do is making your own soundtrack. Instrumental versions are easy to make or you can always hire someone to do it for you. Using your original soundtrack would actually be better for you since you will be attracting more people if your music is good!
For me nah, why make your own if you could just find? if you're not really a fan of creating music then you might just ruin your day after listening to your creation, it is easier to find soundtracks that is encouraging or exciting, that way it can boost your mood while playing. My soundtrack while playing is mostly EDM type of music, Skrillex and Marshmello I feel like their music is energizing me whenever I gamble.