You’re right, nowhere does it mention toxicity, except the entire article.
And you’re right, I am not sure there aren’t any heavy metals in my leather and fabric straps.
And you’re also correct that the stainless straps that I do have which I bought from a jeweler I am additionally uncertain about their contents aside from the manufacturers certification.
But weren’t you talking about silicone?
I don’t know if I can resolve this, but I’ve done some reading and the m2/m4 have some known issues with Linux.
Some patches and configs and instructions are here:
https://github.com/kiosion/alsa-motu-m2
Aside from that, there could be another application that is locking the card which is why you’re getting the resource busy error.
As mentioned here:
https://unix.stackexchange.com/questions/753676/pipewire-pulse-no-sound-playback-open-failed-device-or-resource-busy
And some more issues/troubleshooting specifically with the m4:
https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/3312