I like this Pro Tec pad and use it on several bags: https://www.amazon.com/Pro-Tec-Neoprene-Shoulder-SHPAD12/dp/B00UFCVK8O/
Ultimately, crossbody/one strap carry is best with light loads only for all day use. If you’re carrying more than a few pounds it’s backpack time.
I bought this after my first week of work. https://www.amazon.com/dp/B00UFCVK8O?ref=ppx_pop_mob_ap_share