I'll tell anyone who will listen not to buy a car thats been developed on a new platform for at least 3 years to give them time to find faults in the design in real world conditions. If your playtesting or in early access you are literally playing a prototype, a bunch of content creators spouting off about how its a buggy mess could put a stink on the whole project that people will remember even if its perfectly polished by launch.
Playtests typically involves a full on NDA for this reason. If your playtest is aimed at creators that are allowed to stream it's not a playtest, it's a marketing exercise.
The content creators should work together to make a single bland “it’s fun 😶” video that all of them post. It would technically comply with the restriction.
What is the timeframe in the contract? The quotes only show a tiny excerpt of the whole contract.
I don't see anything unreasonable about this if the terms expire when the game releases or the review embargo lifts. Reviewers can't review pre-release copies of games until the embargo lifts.
If the non disparagement clause remains in effect after release, that's very bad. Impossible to tell which it is from the tiny excerpt provided.