I like the concept of it, but while it's easy to read on my large computer monitor it wouldn't be easy to read on a phone. You may want to consider using a font that is easier to read (a Sans Serif font).
maybe just use the picture on the left as the main image as its very open but full of mixed patterns and contrasting colours that really catch the eye then, maybe a cleaner more legible font for the title.
It might work better across all devices this way. just a suggestion from a fellow creator journal looks great
I agree with the two comments above. An easier-to-read font plus just one picture.
One more thing Sumi, I noticed that some of my (admittedly lame) thumbnails have words near the bottom right where the length of video numbers are placed by YouTube at times. This means my words are covered up. Definitely not good for me. For yours, it would probably only cover a portion of the word JOURNAL, but it's something to consider.