All models of iPad Pro 11" are capable of update to iPadOS 17.x - the most recent release being iPadOS 17.4.1.
As for how long your chosen model of iPad will continue to receive updates is known only within Apple.
Apple does not pre-announce end of update support for its products. However, for iPad, history demonstrates that many models of iPad continue to receive system software updates for five to seven years from release of that model. Update support generally ends when a major version update requires more system resources (e.g., CPU and RAM) than the host device is capable.
With the benefit of this knowledge, you can perhaps draw your only conclusion upon anticipated support for ongoing system software updates.
Also consider that some major App Developers will only provide App updates for two (or perhaps three) previous major versions of iPadOS - and as such, a device may still remain usable with major Apps for an additional two to three years beyond cessation of Apple's system software updates.