DO NOT START BY LEARNING FRAMEWORKS. That's my most important piece of advice. Start out Vanilla, because, as the others already mentioned, libraries and frameworks come and go, but your vanilla knowledge is what always stays and helps you understand new frameworks and libraries (see my HNO for more info).
Also, start by learning the latest version. There are a lot of people who are not sure if it is good to learn and use the latest features right now, but since you are new, everything is new to you, so you should just go and learn how to work with the latest and the greatest. They are already supported on a majority of browsers :)
When starting out as a fullstack dev, there are many technologies and things to consider and learn. I suggest you start out with one topic and work on it until you feel confident using it. Since you already have some experience using HTML, CSS and PHP, why not try to spice things up with some JS? Try to load content from the server in the background instead of using regular HTML links!
In order to learn all that stuff, use the Hashnode search functionality to find posts about learning techniques. As for my tl;dr advice: practice a lot. Make your personal homepage and put it online. Make homepages for your family, your friends, your clubs, whatever. Maybe try to build a browser game, like LotGD. Put everything online, share the links on social media, get feedback and improve your creations. Imho, practice is the only way to become good.