Hey woodworking fedi, how do I repair these in a way that does not cause trouble later on?

Currently they do not go all the way through but give it another 10 or 50 years and they likely will as the wood continues to shrink. So what do I need to do to make this thing usable now and repairable later?

@skye I'm not a #luthier but a guitar player and #woodWorking guy. I'd imagine the original sound of the autoharp depends on having a single-piece back, either by gluing up several pieces (the current back looks like that) or just a single piece of wood. Joints in fine violins are held together with hide glue, which can be removed.