Well, yeah, I’m fairly suspicious of smart home tech even if it has fully documented interfaces that therefore can be controlled by open source software.
It still increases your attack surface.
Unless the entire thing is 100% open source, it still creates privacy and security risks that you will find it hard to measure, manage, mitigate.
I still struggle to see the benefit as outweighing the cost.
But at the end of the day the OP is free to explore and use as he sees fit.
I wonder what would happen if you install the Raspberry pi app directly to your Librem 5. Both use ARM architecture. There are a lot of raspberry Pi apps that run from a desktop environment on the Pi. But I do know that in the ARM world, that it’s not like a PC where any hardware will work with any software and be compatible.