First, I think you're not doing nearly as badly as you believe. The lifts look pretty good.
Second, 77kg. You're only 2 kg short. This is weightlifting, not weightcutting. You don't want to be the tall skinny guy at the meet - you're just putting yourself at a huge disadvantage.
I only watched the last 2 videos, so the following comments refer to those only.
Biggest issue is that your weight is too far forward on your feet during the pull. Right off the ground, shift back toward your heels and keep your weight there throughout the pull. Think about staying flat-footed as long as you can during the pull.
Try to get the bar to contact your body higher - right in the hips is ideal. Part of the early contact for you is that forward weight balance and as a consequence not being able to wait and stay over the bar as long.
Also need to open up slightly more at the top of the pull. Again, this vertical extension could be a product of being forward earlier rather than you just not trying to extend enough.
Could get the elbows higher during the pull under and stay closer to the bar. That will be easier when you fix the balance issue.
This is a good lift. Same balance issue as with the snatch, but to a considerably smaller degree.
Sit all the way into the squat. You're stopping short, and especially as the weight increases, that will make the lift a lot harder. Eventually it won't be possible, and if you haven't been practicing the lift w a full squat, it's going to be risky and quite possibly unsuccessful.
Make your dip shallower and keep your weight completely on the heels when you do it. Unlock your knees and get tension on your quads before you start, and make the dip smooth. Keep your chest back as you dip - knees only, no inclination of the torso.
Stay back over the heels and keep your chest back during the drive as well. Straight down, straight up - then split the feet. Pick up your front foot a bit more and keep the back one close to the ground.