For counter bend, it's not counter flexion. When I ask for counter bend, I'm bending the whole horses body around to the outside as though they were traveling in. Bending through the entire rib cage reaching from the outside hind to the inside fore. It's about moving the shoulders and gaining control of their shoulders. You can also do several small shallow loops (like steer in 2-3 ft, steer out to the track and steer in 2-3ft and back to the track) to help break up his shoulders, so he'll release his neck to you and reach down into the contact. Leg yielding into towards the center of the arena.
The problem I'm seeing is the horse hasn't really accepted the inside or the outside rein and he's not really meeting the contact (he's not over his topline reaching to the bit, you want weight in your rein) you do not want him to be too light. This is very common with arabs. On all the arabs and arab crosses I've ridden/trained I've had to bridge my reins at some point because they're so tricky in the contact and focus on the laterals to move them through before I could half halt. All about laterals and movement of the shoulders and haunches.
He's over flexing to the inside, when you flex him out you're literally wanting to change the position of his shoulders. In the canter, it's moving his rib cage around your outside leg and asking his inside leg to jump into your outside rein to give you control of his outside shoulder, you may need to bump him with your outside leg towards the shoulder asking him to move his shoulder over and inside hind leg so he learn how to connect the inside hind to the outside rein. The mini shallow loops in canter will really help with this.
There is a lot to like here, he's much lighter and floatier in the trot. At the canter he's at a 3 beat and has more jump behind. I think it's easy to be too hard on yourself, instead of looking at it as a process and figuring out new pieces. He's peppy, cute and free in his gait. But there are always ways to make it better and improve. I'm ALWAYS ALWAYS learning something new to improve myself and the way the horses I ride go, always expending my mind on what to pay attention to. I have a PRE I have to really move his shoulders and haunches around before he'll let me ride him, so I'll counter bend in his whole body both directions then return to true bend and constantly return to shoulder and haunches control. With the leg yields always expecting him to release his body to me. With him I have to prioritize trust and obedience when I have that he tries very hard but he rides like a pony. Or my mare going left needs me to keep moving her left shoulder over while I guide her right hind leg in line with her body because that's her weakness (it's usually a diagnol pair and sometimes it's the same both directions) for straightness. On my ottb who can pull like nobodies business and unseat me, I sometimes have to grab my oh sh!t strap just to keep steady when he pulls because there is no way to keep stable and consistent when he pulls. He pulls to avoid releasing control. He'll try running, pulling, etc to avoid the rein while he's figuring out how each rein works, normal green horse stuff. So I ride him going left on circles and going right much straighter to help him as he wants to over bend to the right and not bend at all left. Lots of little quirks with every horse and it's figuring out their crookednesses as well as your own that are influencing it.
I do a lot of in hand with the laterals to educate the horse how to respond to rein aids, as well as move their body in conjunction to those aids. It also shows me when the horse is confused or what they're not understanding about contact or in their body. I move their shoulders and haunches, teach a better half halt and transfer weight to the hind end and also start piaffe that way.