Judo competition is not graded on the name of the technique you do. It's graded on whether you throw the opponent on their back, pin them, strangle them, put them in an armlock, or break the rules.
So yes, you can use improvised or "unnamed" throws, or non-standard pins and so on, as long as it's not specifically forbidden.
But if you've never trained judo, nor wrestling, nor Brazilian jiu-jitsu or shuai jiao or Bokh, then it's unlikely (but not impossible) that your self-trained technique is as unique or effective as you think it is.