ADEME has published advice which must be brought up to date given the corona crisis ....
I am very skeptical of the CO2 equivalent calculations of internet use: a datacenter hosted in France does not produce CO2 once it is built since it is powered by nuke. For us, the FB datacenter is in Ireland and runs largely on wind.
The servers are very polluting to produce. But whether we use them or not, CO2 emissions have been made.
And if we used ASICS (specialized circuits) for streaming instead of using processors, we would gain gray energy.
We will not go back to the time of the caves. It is up to the digital industry to optimize its footprint. But for that it would be necessary to put back the carbon tax for them, otherwise as long as the CO2 is free why bother.