[microtonal]

Samsung nowadays tells you ahead of time how long a phone will get major updates and security updates. I think it's the same with Google Pixel. And they have a list of models and their release schedules:

https://security.samsungmobile.com/workScope.smsb

My qualm with them is though that not all devices are updated at the same time (like iOS/iPadOS/macOS). One phone may get an update the 10th of the month, while another only gets it the 30th. As a result, there is often quite a large window where vulnerabilities are known, but not yet patched (it's even worse with the cheap models that only get quarterly updates).