It ain’t post injury anymore man. That’s the couple of months post fracture where your bone goes thru the stages of healing and you lose ROM and strength if you don’t do your exercises.
Its been a year and with proper rehab your bones and soft tissue should be as strong and have as full a ROM as before your fracture if not more so.
Point is don’t use past injury as a crutch. Think of this as a grip issue because pinky curls and holds aren’t going to help you much. Unless your pinky is so stiff that it doesn’t wrap around the bar fully (this is possible tho unlikely that you wouldn’t have noticed this) targeted rehabby kind of stuff won’t be useful.
Temporary strap use as required is a quick easy fix to continue to develop your deadlift while your grip catches up.
Hook grip is more secure than mixed in my experience but takes some learning/getting used to and never really tolerates volume well. Suits some styles of pulling more than others tho e.g. if you spend minimal time down at the bar like a rip and grip style you’ll find it hard to set the hook in a short amount of time. A bad hook won’t work and can hurt you if the bar tears up or catches on something it shouldn’t.
Maybe a technique tweak like holding the bar lower in your palm could help you also.
There’s many ways to improve grip and for that matter many kinds of grip. To improve grip for your deadlift you should build/overload with exercises/strategies that mimic the way you use your grip in the deadlift and thus have the best carryover. Stuff like in chris_ottowa’s videos are handy. Simple stuff like doing as much work as possible double overhand e.g. deadlift warm ups with a hold at the top can do wonders if you do it consistently and build up over time.
I had grip issues when I started lifting especially on back days and deadlifts. Tbh I just kept hammering the pulling exercises, strapped up when I couldn’t hold on anymore and double overhanded as much deadlifting and shrugging as possible. Grip issues just kinda went away.
I did end up switching to hook for sumo pulling not cuz of grip but because my supinated/under hand kept catching and tearing up on my thigh or windmilling the bar about.