I had this same problem when I first started learning godot. As far as I know there is no ultimate guide to GDScript (excluding the documentation of course) so you have to change your learning style. As long as you know basic computer programming, here's where I started.
https://www.youtube.com/user/uheartbeast - Heartbeast's tutorials were probably my biggest benefactor. Between his free tutorials and his 8 bit godot course I made 7-8 different tutorial games before I could even start making my own. These resources are absolutely invaluable, I still constantly reference the Metroidvania project if I forget how to do something.
There are tons of really helpful tutorials as well on youtube, a lot of them are from very small channels though and often get overlooked. Here are some of my favorites:
There are more of course, you just have to snoop around.
Last of all, don't be afraid to reference old projects. If you find a solution to a problem, there's no need to reinvent the solution every time you encounter the problem. Hope this helps, good luck on your learning journey!