Although older iPhones don't support the latest version of iOS nor do they have any of the new features, they should continue to work for a while. They will also continue to receive security updates for iOS 16. Learn about your options for getting parts and service for Apple devices that have passed their warranty period. Statista (a provider of market and consumer data) publishes a graph showing how long Apple is compatible with older iPhones. Apple will offer support for iPhones (and all the devices it makes) for seven years starting from the last time it sold that particular model.
This suggests that while the iPhone 6s may receive software support for a while, it may not be possible to repair it if it breaks.