Tips?

sumo or LDAR

Sumo, or just use a hex/trap bar (also easier on hip mobility than sumo would be). If you find that your skeletal build limits how well you can do something whilst you're not competing in it and there's a method to get around it, why put yourself through something it sounds like you don't think you're suited for/don't enjoy?

You don't "need" to do anything - unless you're competing in that lift - regardless of what people tell you. Yeah, some things might yield better results, but something is better than nothing, and excelling in something you can do without injury is infinitely better than struggling with something that can potentially injure you.

Rack pulls

For short armed deadlifters, in my opinion, the most critical factor is bar speed. If you are going to make big pulls with big weights, it's going to happen fast. You are never going to be a lifter who grinds out 10-second max reps. The shorter your arms, the longer your actual pull-which means you spend more time in the natural sticking point right around your knees. A longer armed lifter begins to push his hips forward and get his back upright much earlier which means he reaches a mechanically advantaged position sooner. The task for short armed people is to be so fast off the floor you move through that sticking point as quickly as possible.

Speed pulls against chains and bands are the best way to develop this, imo. But just remember, the goal is to always accelerate that bar and move as fast as you can. Sumo might be a solution but the same principles apply regardless.