The 32 comes from us using a bit mask in a 32bit integer. It doesn’t mean that you’ll automatically use 32 different materials at the same time.
You are still in control of what you render at any given momemt, and should be able to control what you present on those lower end devices.
When in doubt, profile!
For instance, what is your current performance bottleneck on the lower end device, and is it a problem or is it ok?