Hey Dec, put what you're asking in the context of what music style you're trying to learn. For example, learning to sing intervals on a scale you're not going to be using isn't important for you to learn. It's important to learn later as you try to expand different styles.
But if you're focused on making pop music, or blues/funk, then it's not necessary if the scale isn't used in that style.
My point is it's good practice to determine whether something is useful for you and your goals, rather than hoping someone will tell you exactly what to practice vs. not practice.
Does that make sense?
There is not a wrong way to practice. The simplest way to know whether you've gone off course is if you find yourself not using what you practiced. It's still not a wrong turn. It's just about adjusting your next practice so it's more relevant to your growth.
That's why people love saying "don't waste your time on YouTube" because it's not a structured way to learn. What they don't say is that it's okay to learn different things at different times, you just gotta know the context of it.
Just remember this is not a sprint. It's a marathon. Don't worry - just focus on studying and practicing it deeply in the context of what your guitar goals are.