Design copyright if modifying assets and template?

Hello,

I have used a flyer template to design a poster for a non-profit. 
The Adobe Express template did not have any 

My final design has modified all the elements, from the fonts to image colors and backgrounds, quite different from the Adobe Express one and the variations produced by the application.
May I use © for that design as mine?
Please, do not tell me to read the licensing notice because I did and it did not clarify me this issue, so 
I hope a person and not an AI bot can reply this and answer my question. 
Thank you in advance. 

Mercedes