I have no info on it. I can speculate, and I'm happy to be corrected!

There is no way that physical media is greener.
Just the sheer production of physical media would be more than the servers, never mind the transportation, space in shops, people traveling to pick it up.
And then, day 1 rolls around and there would still be updates.
10x bandwidth for an hour is nothing.

And I'd consider everything up to the trunk routes of the internet. Ultimate, internet trunks and consumers are going to have internet. A data center peering to the trunks isn't hugely power intensive, the networks are going to exist and the bandwidth is available, it's mostly a matter of cost. So, it's essentially steams datacenter impact.

Could probably estimate it.

If it's able to deliver 150tbps, and we assume steam is using 100gbps networking per server (ultimately, it's just file serving), that's 1500 servers.
Say a server is 1.5kw, that's 1.5kw of power and 1.5kw of heat. DC cooling is about 15%, so 1.77kw per server.
Or 2.7 MW for all 1500 servers.
Round that up to 3MW to account for backups, spares, switches etc.
So, let's assume that the BG3 download took 3MW for 1 hour.
And, I feel, this is an over estimate.

Trucks are 300-500kw. Let's take 300kw, best case.
A single DVD case (let's ignore that this game is on the edge of a 4-layer bluray, and say it's single disc) is 55 grams.
2.5m copies (the lowest sales estimate I've seen) would be 137,500 kilograms, or 137t.
A 44t artic truck can carry 24t of cargo (this depends on the actual truck and local regulations, of course).
So, moving 137t of discs requires 6 trucks.
6 X 300kw = 1.8 MW.
So, if it take more than 2 hours to truck these discs to get them to stores, then transportation is already over the DC power requirements.