My opinion of why a lot of peoples deads are not that much greater than their squat is actually to do with the prevalence of partial squatting (or at least lack of proper depth) in most gyms.
It's a lot easier to add weight to a squat at the sufferance of depth whereas deadlifts are a lot more honest about how much you can lift.
If you think you're limited by grip strength then use double-overhand for warmup sets and mixed for your working sets. Also buy a ton of chalk and smother yourself in it (focusing on the hands!
). Don't deadlift with gloves even if it does mean your hands look like a gnarled tree's bark. If you're still struggling buy some straps. Finally, if you still can't lift anymore with solid form then you should probably take a look towards your squat form and see if you're actually doing them properly.
But that's only based on my experiences in my gym where most people 'squat' (and I use the term with hesitation) 20-30kg more than they can deadlift.
It's a lot easier to add weight to a squat at the sufferance of depth whereas deadlifts are a lot more honest about how much you can lift.
If you think you're limited by grip strength then use double-overhand for warmup sets and mixed for your working sets. Also buy a ton of chalk and smother yourself in it (focusing on the hands!

But that's only based on my experiences in my gym where most people 'squat' (and I use the term with hesitation) 20-30kg more than they can deadlift.