Great to see you are considering ways to improve and get experience. That is the first step to improvement.
IMO, a lead sled might seem like a good idea right now, but since you can't get behind the rifle on a lead sled in the way you will eventually want to shoot it to achieve real accuracy, it is more of a hinderance and a builder of bad habits than something that you can use to make improvements.
ARs have a lot of stuff moving internally that tend to make them less accurate than bolt actions, but you can still learn a lot about improving your set up and gaining consistency that will make you a much better shooter. It takes time behind the trigger and your ability to gather information about what works for you.
Unfortunately, I don't think there are many short cuts.
I would suggest you seek out some shooters who you think have figured it out and watch, ask and learn.
Most of us have had to go through that process to finally figure out how to consistently shoot under 1/2 MOA, and some of us may eventually make it to 1/4 MOA if we were particularly attentive.
Don't get discouraged if it takes a bit of time. If you are particularly self-observant, it moves along quicker, but some of us take longer to build that skill than others. Unfortunately, I don't think there are many short cuts. Just watch out that you don't get too confident along the way. That's when I usually throw the next shot and mess up my groups.