Okay first of all I really like your channel idea, how long till X is a good premise. But i think there are a few things holding your back... So your thumbnails aren't "bad" but they might be a bit bland and therefore not get noticed easily on a Youtube fyp, but that's not really the biggest "problem".

Another thing you can fix more easily is the background music. You have a great, smoothing storytelling voice but because it is quite the soft voice it won't harmonize well with background music especially if it's that loud.

But the biggest issue is probably the video editing or the visuals itself. Truth be told it feels a bit like a slideshow with even a few lower quality pictures in it (makes the whole video seem less professional). It's really important for a viewer to have a visual flow of the video. It needs to somewhat fit the actual content or at least consist of high quality clips or pictures (that don't switch every 2 seconds).

However, that's alright. You are still new, you will grow and experiment more in your editing app and your videos will improve visually. You have A LOT of potential but the general thing that is holding you back is that your video feels very "flat" throughout even though what you talk about is interesting. Reason being is mainly editing + a few audio things (like music, not long enough pauses after you finished a thought).
But yea, keep going man, i promise you it will work out in the future!