Assuming I go through all the textbooks on this site, and I've studied them, what can I do? I mean will be able to build myself a radio all by myself from designing the PCB? What other devices will I be able to create?

 

Hello there. welcome to AAC!
don't worry,I remember you! https://forum.allaboutcircuits.com/threads/are-fanless-chromebooks-ok.114474/post-1637316
https://forum.allaboutcircuits.com/threads/are-fanless-chromebooks-ok.114474/post-1637318
I was just kidding. Now go away! Haha! Yes!You will be able to build a radio all by your self. you would be capable of not only designing a PCB but to simulate the circuits of your radio using the various electrical components necessary to achieve your goal.
Oh yeah .I almost forgot ,you have an entire community here, to assist you, in your endeavor. That means. We have brilliant brainiacs.

 

What other devices will I be able to create?

Going through and understanding all the textbooks should allow you to build circuits that have already been designed, and hopefully, understand their operation.
What devices you can create will depend upon your creative ability to extrapolate from what you have learned.
That, none of us know.

 

Assuming I go through all the textbooks on this site, and I've studied them, what can I do? I mean will be able to build myself a radio all by myself from designing the PCB? What other devices will I be able to create?

I think it's important to change your perspective- Let's change your question to this one instead:

If I don't read the materials (and other materials) freely available to me to learn electronics, will I never be able to do anything with electronics?

The answer to that question is _YES_.

Here is also an excellent start: Will get you farther initially than almost anything else:

Title: Understanding Basic Electronics, 1st Ed.
Publisher: The American Radio Relay League
ISBN: 0-87259-398-3