Not completely. If it's one that does mapping, that's all stored on the cloud.
You can prevent some of the telemetry with a pi hole, but be aware that every run will end with a notification of "communication error" when the Roomba tries to report on you
iRobot still sells all the parts for their old, non-cloud vacuums if you don't mind buying used and doing DIY parts swaps. They're very repair friendly: No special tools required and easy to take apart.
I run a ~5 year old Roomba, that I just never connected to anything. I control it via the physical buttons and it works just fine. Is that not an option anymore on newer models?
You can prevent some of the telemetry with a pi hole, but be aware that every run will end with a notification of "communication error" when the Roomba tries to report on you