Y'know, this is in this weird spot where it's right between canon and as seen (which, by the way, can be explained even with canonical things). If it was truly as seen, the shots would have gone way wide. If it was truly canon, the Reps would be scrambling for a new candidate now.
The explanation for Stormtroopers' shoddy marksmanship on screen in A New Hope is because Vader wanted Leia & company to escape, but by the skin of their teeth, so that they would basically drop their guard the instant The Falcon took off from the Death Star and not realise there was a tracker bug installed. If Vader just let them fly off unopposed, that would probably be hella sus, and they'd probably pull over at the first asteroid to find and chuck said tracker bug. So the Stormtroopers were specifically instructed to shoot to thrill, not to kill.
When faced with opposition without plot armour and reasons to keep them alive, Stormtroopers are fucking brutal, as seen in The Empire Strikes Back - Hoth was somewhere between a decisive Imperial victory and an Imperial Curb Stomp
They literally are. Their most common chambering is an ideal white tail cartridge.
hunting human rifles.
let's be honest, it was designed as a lightweight emergency carbine made of space aged materials. 60 years later we're arguing if the founding fathers meant bump stocks and cmags when they said well regulated militia.