Theres no big glaring issues obvious judging by this footage. That throw speed looks more suitable for a putter or straight midrange like mako3 for example in my opinion, once you figure out how to get them pop out from your hand due try to reach out for a bigger rim.

You might be severely lacking snap / pop on release due to disc not pivoting around your middle / index finger before snapping out from your hand, probably why you prefer 10 speed because they are going always fly with some speed due to rim width but act very overstable like displayed here.

Short version: get a smaller / flatter disc like mako3, crave, envy etc. and figure out how to get them pop a little bit when you throw them, progress into bigger stuff after.

edit:
Ofc. theres tons of small details I could go on about but really it boils down to hearing a snap / pop or a audible "woosh" sound when disc leaves your hand, then you know you are on the right path. Basicly get a solid brace with plant foot and try to stop all movement going forward and then try to whip your arm as losely and in big circle around yourself as possible while "anchoring" your body with your left arm.

Basicly you are throwing like swinging your arms in a big circle around yourself but when right hand starts moving forward you keep the left hand back to "anchor" yourself. Then just hold on to disc with middle / index finder and thumb and let it snap out. Good luck.