90hz screen with 180hz polling is what my phone uses as well, it's nice that the deck has now caught up to that.
Also remember to leave your original deck on when downloading games on the new one so it can transfer them locally, which should be faster. There's a setting for that, but I think it's on by default.
According to the documentation, you should be able to https://help.steampowered.com/en/faqs/view/46BD-6BA8-B012-CE43. Unfortunately, I don't have big enough games to test, and I think it detects that my internet bandwith is higher than the connection to the Deck
A Steam Deck, or a PC running in Steam desktop mode can host network transfers. PCs in Big Picture mode, and custom launchers can't transfer their files out over the local network.
But is it "(A Steam Deck), or (a PC running in Steam desktop mode)" or is it "(A Steam Deck, or a PC) (running in Steam desktop mode)"? In any case both cases include the Steam Deck as a capable device, it would only be a matter of changing to desktop mode
My router is a bit old and its 5GHz performance seems to be rather lacking. I still think the main problem is I'm not testing with a big game. I'll try and post later something.
The local transfer compresses it with the same format the CDN would use, so if the local PC turns off, it just continues via Valve's servers. The downside is that the compression is quite aggressive. My PC with a 5950X can only go like 300Mbps on local transfer, so the CDN ends up being faster for me since I have gigabit internet and the Deck can get 600 Mbps even over WiFi.
For people with slow Internet speeds, it's obviously a great feature though.