Fixed bar, or rotating handles? You make the call. For me, Imma choose something that has the capability of allowing my wrists their natural rotational ability in order to ensure the most longevity out of my joints and tendons. That said, you do you. Either way, pull-ups are an excellent upper-body exercise, simple adjustments to had position, and even torso position, can alter which muscles are biased more. A little closer grip and lats are gonna kick in. A little wider, teres. Torso leaning back; again, more lats. Etc. Play around with all different angles and decide which one fits you and your desired muscle target best. You’ve got my starting point recommendations and reasoning above to get you started.