may just be the one swing you posted or maybes an overall tendency but shoulders maybes already set a little ways 'open' at address
from that tee box it's a little difficult to see what the 'line' is down that hole but even allowing for parallax you look to be set-up looking down rightfield (feet hips) edge of the fairway? with shoulder line a tad leftfield
it's true that a swing motion has to be 'connected' motion in sync but it has to be connected whilst still being able to maintain a good natural 'width' - distance the butt end of a handle is to the center chest, sternum
if you go on your youtube swing page go into settings & choose speed 0.25 you can easier play & pause the motion have a look at takeback when the shaft is first parallel to the ground check the lead arm it's starting to give in at the elbow (ideally you want it comfortably 'straight' not rigid but not starting to bend any)
likely reason for this is you been looking for that 'connection' (well meaning PP advice) but it's being a tad more of a hindrance here - real annoyingly golf is a 'goldilocks' game so just enough of something but not too much at the expense of something else that's real important, in this case - width - although don't want the arms flying either a ways outwards & upwards neither drawn hardback across the chest any so club behind the legs - but it's equally real important that the arms aren't being held tucked back into the body any in the backswing as the distance between the elbows also tends to widen some looking to keep the elbows that good relaxed same distance they were at address during that first part of the takeback
to have good 'connected width' the left upper arm is looking to stay more just 'lightly connected' to the 'pec' side wall but with the left arm 'relaxed straight' so that allows the right elbow when the shaft is parallel to toe line & horizontal to the ground to be a couple inches away from the right side - so not tucked right in up close
as if it is you get atop the swing with the right upper arm & elbow being a ways tight against the side which also puts the left arm plane a ways under the shoulder plane
leads to it all tending to get real cramped up at the top with the width that started at address being lost
any good swing needs a 'model' that has natural connected width going back atop, then the weight pressure moves left first at transition & so the downswing is naturally narrowed some - as the motion works in sync from the leadside up bit like a reverse spiral it's how the angles, the levers can be kept into strike how you get speed through the ball
already narrow atop this then can't happen by product of it is it then leaves too much weight on the trail leg
tends also to lead to losing the spine angle some atop the swing as folks more have to straighten up spine angle some, along with the right leg over-straightening some
from an upper body/arms too 'tucked in top position' the arms shoulders just start back first, weight doesn't get into the leadside to start the motion & then hips chest arms all work back together the weight staying bunched ways too much on the trailside through strike (so pretty flat right foot) then arms & club tend to have to work independently through the strike & swing direction through impact to leftfield
as you take the club back try to look to keep the distance from the butt end of the club at set-up the same until the hands/wrist 'set' upwards, then look to keep the hands that similar distance infront of the chest & allow the right arm to fold (elbow down to ground) but not being overly 'heldback' into the rightside - look to see if you can get a decent 90º right angle at the right elbow at the top with the shaft being more over top of the tip of the right shoulder
from the top see if you can then feel the weight just bump some into the left leg as your back stays looking to target a fraction, then swing down left hip rotates & truns out of the ways & upper body/chest turns through, right knee working to left knee, right foot up on toes, part of the balanced finish the shaft is angled more across the nape of the neck pointed back over the ball/target line not vertically 'down' the back clubhead down to the ground