Let's start with the newest of those phones. The update for the Nord 2 is labeled OxygenOS 11.3.A.10, and it seems to already be rolling out according to some user reports. It's a 245MB download when you get it.OnePlus Nord 2
It comes with battery optimizations for PUBG and other gaming titles, which should hopefully put an end to the unusually high battery drain some people saw when gaming. Additionally, a face unlocking bug has been fixed, camera app stability has been further improved, and the security patch level is now August 2021, which for once is current (and that's not always a given with OnePlus).
This update is now seeding to Nord 2 units in India. Moving on to the OnePlus 7, 7 Pro, 7T, and 7T Pro, these handsets are receiving OxygenOS 220.127.116.11, which also contains the August 2021 security patch level.OnePlus 7T
Aside from that, you're also getting Ambient Display improvements, such as the addition of the Bitmoji clock. This lets you put your personal Bitmoji on your Ambient Display, and your avatar will update throughout the day based on your activity and things happening around you. There's also a new screenshot feature for the Ambient Display, and the stability of NFC has been improved too.
Finally, the OnePlus Store will be installed in regions where it hadn't been already. As always with OnePlus updates, expect all of these to only make it to a small subset of devices today, with a broader rollout coming in a few days if no show-stopping bugs are found.
Not that, it's just so incredibly illegible and can make you read wrong time because some idiot thought coloring leading number of an hour was a great idea for some reason.