A few of the Xaiomi's and Viomi's are rootable. I have a Gen1 Xaiomi and it's brilliant. I got ssh access to the ubuntu install and installed https://github.com/Hypfer/Valetudo and run it 100% local via my home-assistant install.
One of the first steps when rooting is usually to block outgoing and incoming in iptables (it's a fairly standard ubuntu install after all) so you don't lose root at any point, so the risk is minimal. Not to mention I have a dedicated non internet routable IOT network specifically for this reason.
Not sure I'd connect a device from these vendors to my home network.