For what it’s worth, it looks like the desired Debian package is iwlwifi.
https://wiki.debian.org/iwlwifi
I don’t know if Elementary has the same package, but while on Elementary, you could create a Debian virtual machine, use Debian to download the package to a USB stick, and then install it on PureOS from the USB.
If you have a USB-to-Ethernet adapter, you could install it directly from PureOS by enabling the Debian non-free repo.