I’ve seen this linker error before, it has to do with Mbed adding “wrapped versions” of certain functions and the configuring the linker to use them. It looks like the linker flags for the minimal printf library are enabled, but the library isn’t actually being linked. You could try explicitly disabling or enabling minimal printf in your mbed_app.json.
By the way, you might be able to sidestep this and other Mbed exported issues by using mbed-cmake instead. It provides a lot of the same benefits while being far less janky (in my experience).