The aftermarket is huge and the Sportster line has so many different models over the years, it's not always easy. Even when the product description says it will fit your model, depending on the set up, it may not.
This is where a dealer can be helpful. They should know what fits from assessing your machine and what you want and need. And if it doesn't, they should stand behind their product and work with you to find something else if the original doesn't function as described.
I know it can be confusing and accessories are not cheap.
A highway bar can be helpful to prevent some damage from a tip over. The real benefit is having another place to mount foot rests.
Good luck.
I