This is a huge step up from the existing promise. Currently, OnePlus pushes three years of updates to its numbered series flagships, while two years of upgrades to the Nord-branded lineup and three years of security patches.
OnePlus Android updates
In comparison, Samsung back in February announced that its flagships would get four years of Android OS upgrades, and its midrange Samsung Galaxy A53 launched with the same length of software support. Google is promising five years of security updates and three major Android OS updates for its Pixel flagship phones. The mid-range Pixel 6a will also yet five years of security updates.
Regardless of the competition, four years of OS upgrades and five years of security patches will make customers put a great level of trust as software support is often considered one of the purchasing decisions. This will also allow customers to keep their devices for a longer period of time after paying a premium. This is in turn good for the environment as there will be lesser phones to recycle.