By the way just because the official limit for HDMI is 10m, that doesn't mean that a longer cable can't work. I've been running a projector for decades, which was connected with a15m cable for literal decades. It might work, it might not, you'll know when you try.
Usually the link either works or it doesn't. The picture doesn't get bad. It's a digital signal, it either gets decoded correctly or not. In rare edge cases you might get a signal to drop occasionally though if it's too long.