I think you are right that there is not a ton of beginner tutorials and training specifically starting with PHP7. It's still pretty new and I suspect good training is still forthcoming.
You might be better off looking for PHP books rather than online tutorials? Books tend to be faster to market. But there are also some decent courses I'm sure. For example https://www.udemy.com/php-for-complete-beginners-includes-msql-object-oriented/
If you were to learn 5.6 as a beginner, you'd be just fine. By the time you get to intermediate and higher levels, learning some additional differences of PHP7 won't be that big of a deal since you'll be used to how the language works.
There is not much that is completely deprecated AND removed between 5.6 and 7. The skills will transfer just fine, and most cheap hosts aren't even on PHP7 yet or have that as an option. If you browse job postings or look on github for projects to work on, very few will demand only PHP7 support.
It's kind of like this. If you learn mechanics but study on junkyard cars and trucks that are 20 years old, then suddenly you need to work on a 5 year old engine, you will have enough foundational knowledge to figure out the modern stuff much easier because "mechanics", in general, is transferable knowledge.
When we had to stop using mysql_ functions and switch to mysqli_, it wasn't exactly earth-shattering. 90% of the time we just renamed the function call. It wasn't a huge learning curve. Moving to PDO is a small learning, there are a few concepts to learn, a couple extra functions to call.
Once you have some good foundational knowledge of PHP and can work with code and build small apps or whatever, those skills will transfer to PHP7 just fine. You just read up on some of the differences and things you can do, and then update your code if you like.
I've been using PHP since late 90s, 2000s, probably started on version 3. It's not like the training I've done or books read are worthless just because they are superseded eventually. It's all just experience and evolution of knowledge.
You can study a PHP 5.4 course and then get stumped on a PHP7 project just as easily as you could study PHP7 and then have to work on an old 5.4 project and get stumped. As a programmer, you may have to work with code written to any given version by any given programmer at any given skill level. It won't hurt you to learn something that's slightly out of date. Just keep learning and updating your skills over time!
phptherightway is a great resource. You can be out of the "beginner" designation in a month or two and those resources will make much more sense then.
If one course doesn't cover a topic well enough, then you go search out just that topic, or post in your class forums and the instructor will help out!
PHP is literally known to be a language so easy to learn that lots of people learn "just enough" to start writing sloppy, insecure code almost right away. You can start dumping stuff into variables and spitting out text to the page in about 10 minutes. A question/answer word game is a one-session exercise.
Don't be discouraged! Just ask questions and the people here love to help! I'm also sure you haven't exhausted all the possible decent PHP tutorials on Youtube, keep hunting!