Series 3 with ios 16 and above

iOS 16 is not released yet but rule of thumb is minimum requirements not the other way around so

Apple Watch Series 3 - Apple

• Apple Watch Series 3 requires an iPhone 6s or later with iOS 15 or later.

but mind you, Apple Watch 3 will not support the upcoming watchOS 8 so it may not be a prudent purchase

Read the last paragraph in the post above.

Watch 3 will not update to watchos9 when it is released later in the year.