Already there. This is youtube’s attempt to get you to chose the next video you see in the final 15 seconds of the playing one.
I don’t see anyway to stop or block it. Anytime you pause a youtube video, suggestions frames overlap the video content too.
May I suggest using 4kvideodownloader. $15 & you own it. Downloads 95% of all youtube videos & saves them to the local drive of your choice, & you wind up with nothing but the full video ! - no commercials, popups or other unwanted stuff.