Technically yes, practically no.
The reasoning process takes time to build. Diesel and gasoline require different mental models of combustion, different failure modes, different map interactions.
The practical recommendation
Pick one track and go deep until you can work independently on an unfamiliar car. Then adding the second track is much faster because the reasoning process transfers.
Most people: diesel first if your market is diesel-heavy. Gasoline first if you focus on performance cars.
What you should avoid: buying both courses in the same month hoping to absorb them simultaneously.
Start with the track that matches your market: Diesel Fundamental or Gasoline Fundamental. Go deep, then expand.