Ok cool, that may mean you are indeed doing USX picking. A slo-mo close up of your fast tremolo could give us further confirmation.
I think your playing is already great! Not many people can play that fast. You are already an advanced player, which means it’s challenging for all of us to spot the tiny details that may be holding you back to get this lick to 100%
So, I think the challenge now is to figure out what kind of mistakes (if any!) are happening when you play the lick at full speed. Is it hand sync? Is it a repeated note? Is it that you think you are sweeping when you are in fact alternating? Once we know the path may become clearer!
One suggestion could be to try and play 5-6-7 on each string, ascending all 6 strings, using the Yngwie system (DUD - DUD etc.). Try and film that in both slow motion and normal speed, and let’s take a look.
That is basically the same as the Yngwie lick you are practicing, but we have simplified the left hand (and made it less musical unfortunately)! but this 5-6-7 on each string is a sound we are all familiar with, and it’s much easier to avoid fretting errors, so it’ll be easier in the video to check if all the pickstrokes are happening at the right time, etc.!