So...
I got a user it running on my telegram account. I can use !ydl and a URL to get a video from YouTube and send it in the chat.
And it took me over 4 hours to make the video <=720p and make a thumb actually show up on the video...
It can't be bigger than 90px on either side so I have to resize the one I take from YT...

And oh boi, it works brilliantly now :3