Here are my thoughts after watching the video...and this is coming from someone with serious recall issues. Serious. Recall. Issues.
(1) Was Maxx supposed to go to you or your OH? Wasn't clear to me, probably not clear to Maxx.
(2) He's way, way, way too far away. And he's already distracted. Start when he's literally a metre away from you and probably on the point of checking in with you anyway. You can also use a long lead so that he has no choice but to come to you (I'm guilty of not doing this as I hate long leads).
(3) Calling him over and over and using different methods (various whistles, his name, kind of a cue word?) just makes it all noise to Maxx. That was 'blah blah blah, blah blah' to him. Teach the recall before you teach the cue, then use a consistent cue. Until he can do it stone cold, only use the cue when you'd bet $100 that he'll come back to you. It's hard not to keep saying "Here, here, here" - I'm VERY guilty of this when I panic, even though I know it's futile. But every time you say the cue when you know he's not going to come anyway, you are making it more and more meaningless. Set him up for success - only try for a recall when you're willing to bet that $100. Otherwise you are better off trudging after him, putting him on lead and trying another time when you can control the environment better.
(4) Treats should be in your hand as he's running toward you and smack into his mouth as he's skidding to a stop in front of you. Also for that long of a distance, major jackpot (multiple treats given one at a time).
(5) Make grabbing his collar part of the game so in an emergency you can grab ahold of him without startling him as soon as he gets to you.
(6) Vary on lead time and off lead time. So on lead for 2 minutes, then off for 5, then on for 1 then off for 3. Just an example but the idea is to make snapping on the lead random so it's not negative. You can also give him a treat every time you click on his lead. I don't know if this is proper doggie training, but Carbon sure does love to have his lead snapped to his collar because he knows that treat his coming.

(7) You can reinforce your recall cue by using it before every meal. Ask Maxx to wait, put down his food, give the cue and he'll barrel towards you. This is a guide dog tip from
@Boogie .
Others please feel free to correct any of this that doesn't seem right. As I said, Carbon and I have serious recall issues, so I can't really preach from a point of success yet, can I?

