FWIW, I tried the dwc2 overlay again with kernel 5.4.0-1021-raspi - as before in #21 this changes nothing - network still dies during first major (>100MB) download, while other USB ports continue working.
On the plus side, the Pi can now actually boot with an external NIC plugged in. I'm not sure if the issue I had (boot getting stuck with external USB Ethernet adapter) got fixed or a hardware change I made (Apple USB Ethernet adapter -> generic RTL8153-based adapter) is responsible.
FWIW, I tried the dwc2 overlay again with kernel 5.4.0-1021-raspi - as before in #21 this changes nothing - network still dies during first major (>100MB) download, while other USB ports continue working.
On the plus side, the Pi can now actually boot with an external NIC plugged in. I'm not sure if the issue I had (boot getting stuck with external USB Ethernet adapter) got fixed or a hardware change I made (Apple USB Ethernet adapter -> generic RTL8153-based adapter) is responsible.