This is just a matter of practice, tbh. Like, it's hard at first, especially to get the laser at a height you want while the turn around laser input. Based on what you're saying I'd recommend practicing out of a run for a while so that you cannot possibly turn before you enter the air.
Also if you don't hold a direction during the second to last frame of the jumpsquat animation, your horizontal jump speed is massively reduced comparatively, to at least 60% of what it would have been (a max of 1.02 instead of 1.7). So, basically, practice the following: hold the direction you're dashing until you're in the air, then once in the air do the turn around laser input, then hold the direction you're going to make sure you keep yourself at or above your terminal aerial x-velocity (+/-.81963) until you land, otherwise you slow down gradually based on the game's idea of air resistance, and based on your acceleration due to your input's influence on Falco (ie. slowing down by holding left). If you're above a certain speed, and input the turn around input as lightly and as quickly as possible (as to minimize the influence of your inputs on Falco's momentum), you should still land going faster in regards to your x-velocity than Falco's terminal air x-velocity (going faster than ~.82). The difference is incredibly visible, so you don't have to hack the game to visually see the difference of what I'm talking about once you get it a few times, but I can potentially make a gif out of this, so everyone can see the differences in takeoff speed, if anyone wants to see the difference off the bat.
https://www.youtube.com/watch?v=tY3XugmyMow this is highly related to what I'm discussing in this paragraph.
If you want to double check what I've posted in terms of numbers, which I strongly suggest getting in the habit of double checking things you read or hear, or directly familiarizing yourself with the means of doing so, you can use a 20XX 4 beta image to gain access to their reworked debug mode's floating point number displays, to show Falco's in game velocity information on the frame it's applied. Feel free to direct message me to ask any me questions on how exactly to do this. I think there's other ways to double check this, like using Dolphin's debug mode, so I might edit this post in the future to include those methods.
I dumped a lot of velocity data from the game in making this post so I'm probably going to clean that up and post it somewhere at some later point.