Steam is getting so far behind on updates its ridiculous. The client is set to update when I am flaked out over the keyboard and to stop when I snap out of it. Instead Steam elects to update games 3 and 4 weeks away. This is useless in the extreme. Ideally game updates should start immediately at the specified time and sequentially continue until the end of the period.
Blizzard and Bethesda both support specified times to download game patches. Blizzard tends to update games more frequently so limiting it to overnight is desirable.
The Bethesda loader often demands a user sign in again and again. This is a serious nuisance that is not seen with other loaders.
NO SCHEDULING AT ALL
Origin has no feature to limit downloads to a specified time. Then again Origin has been bleeding games galore due to the lack of support.
Ubisoft Connect also has no feature to limit downloads to a specified time. Ubisoft does support Steam linking but the API is very limited for maintenance purposes.