As some one with professional graphic arts experience, you are both in the wrong and neither of you should be taking any credit for a lightly modified template. The fact that one of you is slightly more wrong than the other is irrelevant. Neither of you "created" this under the law, so both of you STFU, and withdraw your claims/submissions.
I personally did not submit the work created on top of canvas layout for the Art contest. On my end it is all good. I modified the template as permitted in the canvas.com platform and shared on twitter using their share button and downloaded from my subscription. This needs to be super clear from my end. I myself never submitted the work as my art I just noticed it on the thread. It is not submitted by me. Canva.com does allow those modifications so there is no legal problem to do that and share your memes on social media. To post it on an art contest I do agree.