IANAL but no, executives are not actually legally required to increase shareholder value.

They generally are aiui. Bluesky was formed as a PBC, which is basically a corporation where investors cannot sue for deralict of fiduciary duty.

https://en.wikipedia.org/wiki/Dodge_v._Ford_Motor_Co.#Judgme...

Allow me introduce you to the inception of enshittification

The section you linked to says the decision was non-binding, and the next section includes multiple quotes disputing the idea that such a legal requirement exists.