I've got a Tempest gravel bike from Planet X that came with drops and the Apex HRD groups. It works well but the whole drop handle bar positioning is a very literal pain -- I ended up with crucifying back pain while touring East Germany last summer. I want to change to a Jones bar (like a riser bar but with greater choice of hand and body positions) yet can't find a simple way to transfer the brake and gear shifter. The only option seems to be to change the entire Apex drive train, which is very expensive. Any advice?
The SRAM Apex line includes flat bar trigger shifters.
I don't think there are flat bar brake levers compatible with Apex hydraulic calipers, so you'd be looking at getting separate MTB levers and calipers. SRAM MTB and Road levers and calipers are not compatible with each other - see this answer.