I'm sick of sling bags over the shoulder, so I'm thinking of getting the Spider Holster for when I want the camera accessible.

Or a waist bag like the Mountainsmith Tour Lumbar Pack when walking around. On the picture, the straps are optional if you're carrying less than 10lbs.

All the popular bag brands, Peak Design, Wandrd, Wotancraft, have sling bags that could easily convert to waist bag. Sling bag is the current youthful fashion. I think waist carry will make a comeback, per the usual two-decade cycle.