How long will Apple continue supporting iPhone 6s? Posted 10.30.20

Apple supports hardware for a minimum of 5 years after device production ends. The larger memory models (32 & 128 GB) were only discontinued 2 years ago and the original smaller memory models (16 & 64 GB) 4 years ago.

see -> Vintage and obsolete products - Apple Support

As for iOS support and updates, Apple has no published policy on how long they support the OS for any device.

No one here could possibly know as we are all users on this user to user only forum. I was actually surprised iPhone 6s received iOS 14 this year. So it's end of support life can't be far off in the future.

You're welcome.