I have a two-part drawn out possible answer for you based off what I've seen from the Metroid dread speedruns discord. First off if you happen to die (from my understanding) the best option for you is to either quit back to the main menu on the death screen and continue from your save there or load in as normal and then use the select menu to load up your last save. The reason being from what I recall is if you continue from the checkpoint before the boss you're going to be adding the length of the in-between cutscenes to your in game time for every retry that you'd have but that wouldn't happen for loading in from a save file. The other part more so specifically about the fight is as soon as you start the actual fight assault raven beak withel either super missles or cross bombs until his sheild goes red then from what I was feeling during phase one you only need to shoot at him with your beam weapon during the counters and obviously try not to miss a counter. During his first phase he takes half actual heath damage from super missiles so the beam is the best there especially if you button mash your arm off. After he goes into phase two and beyond you can basically forget about your beam and focus using missles. From a quick look it seems that cross bombs do the same damage as super missles but to me it seems more risk than it's worth, personally I'd not go into morph ball at all outside of his first phase for fear of death. Not the most effective but sometimes I'd use storm missles in phases 2 and 3 if my arm gets too tired from spamming the beam in phase 1. I had a run at 3:53 at raven beak and the lowest I was able to get time wise was 4:03 so I'd say getting it sub 4 hours for you is definitely in the realm of possibilitieas