Could probably be stated more diplomatically, but the point is excellent. Based on the type of diving the OP does, a single tank BP/W is the most logical next step, with adding a slung pony the logical step after that. The sidemount versus backmount question is more reasonably addressed if and when the OP is ready to start training for dives that actually require doubles.Use the right tool for the job. You don’t have a use case for side mount.