Don’t be too hard on yourself!
There’s nothing that kills creativity better than being judgemental towards yourself, and tbh, you can’t expect to write amazing music after just 2 years of playing. It really takes time to learn an instrument and it’s very hard to be creative when your focus is on other things like technique and finding your way around the neck, etc.
If you feel like you have trouble writing stuff, honestly, just continue doing it and you will get better. What i do is i just keep writing and writing and even if a lot of it sounds like total shit, i see it as practice, so i just throw it away and move on. Eventually you will stumble upon something that you think sounds nice and then you build upon it. But other than to just keep grinding, one thing that has helped me a lot is transcribing music – it developed my ear more than anything else and in my opinion it’s like the most important thing to practice when it comes to music. Learning to play a lot of music is also a great way to get insight into writing and how it works, especially if you explore different genres. So try to move away from using tabs – don’t instantly force it, but take small steps away from it and eventually you won’t need them at all and they won’t be as accurate as your own transcriptions anyway, for the most part 
. This will help tremendously in all aspects of your playing, i promise you.
So just continue to work hard, but remember that playing like Synyster is something that will take a huge amount of time and effort and it’s really a long term goal. You have to enjoy the process of getting there so try to find smaller goals that help inspire you and keep you going 
My mistake was pushing too hard on technique to achieve my grand vision, which lead me to often forgetting to enjoy just playing the guitar. And then once when i finally started to get really good technique, i still felt like a beginner in some aspects of my playing because i had neglected them for so long.
Don’t know if this helps, but i hope so For me it’s hard to give specific ideas on how to get better at playing the guitar. The most important thing by far is the mind set you have and how you approach it.
And by the way, funnily enough, i got my first guitar on my 15th birthday as well! I was always so worried that it was too late to get really good, but i’m now convinced that’s not the case for anyone, at any age (well almost)! Not that i’m anywhere near where i want to be, but still 
