I looked into whether the update policy of the Phone (2) was worse than that of other models from the same period. The standard is based on other flagships released around the same time as the Phone (2) (mid-2023) or earlier (late 2022 to early 2023).
(To assume Nothing followed other companiesā policies or industry standards, devices released after 2 are not considered)
Android 13 -> 15 (2 times)
Sony Xperia 1 V,
Android 13 -> 16 (3 times)
Xiaomi 13, Vivo X90, Razr 40 Ultra, HONOR Magic5 Pro
Android 13 -> 17 (4 times)
Oppo Find X6, OnePlus 11, Samsung Galaxy S23
Android 13 -> 18 (5 times)
Google Pixel 7
Phone (2)'s update policy appears to be neither good nor bad, just average.