I've had Rotties for over 25 years now, a lot of them since I did rescue and fostered. He is a cutie and looks like a nice temperament to boot.
I agree with everything LeoRose said. Wouldn't worry about a little grass eating unless you use chemicals on that grass or he's doing it obsessively and vomiting afterward. Unless there was a break in the video and you did take him out first thing after opening the crate in the a.m., I'd change the way you're doing it and take him out as soon as he's out of the crate, then feed, then take out again.
There were a few other things I'd change. First, there's something hanging down into his crate (yellow leash?). Don't let anything do that. If he pulls it into the crate he can chew it. If it's fixed somehow and won't pull down, he could get it wrapped around his neck.
You're chatting away to him constantly. To a puppy, that's incomprehensible background noise, and you'll only teach him to ignore it all, including his name. Sure, you can talk to him a bit, reassure, etc., but don't just keep up a non-stop stream, and leave his name out of it unless it's something he should respond to. Then make it consistent and distinct every time.
LeoRose is right about name response. Wait until he's looking away but not with his attention focused on anything in particular, then say his name, loud and clear. If he turns to look at you, reward instantly. A clicker can help with this because it lets you mark the instant his head turns and gives time to get the reward to him after. If you're in corona virus lockdown, don't have and can't get a clicker, you can just make a distinct sound by clicking your tongue as his head turns toward you. You can use that sound for other things to mean, "Yes, that's what I want, reward coming."
It looks like the treats you're using are pieces of his kibble. Might try a soft treat a little tastier. Small pieces of hot dog or cheese work well.
Maybe just because it was on video, but you didn't praise him for pooping when he was doing it and give him a treat immediately. By the time you were praising, he might have thought it was for walking away from it or something else and it all blended in with the other chatter. Make your praise distinct and consistent and do it while he's squatting. Good boy, Bane!
You don't want him pulling on your pant legs like that and don't want to use anything negative to stop him, so distract him with something better. Carry a ball or some favorite toy, give it a little roll or short puppy toss or wave and get him involved with that instead of your pants leg.
Good luck and have fun with him.