Apple's recent iPadOS 17.x updates have indeed caused difficulties with many third-party USB-C hubs and connected devices. While core built-in hub devices (e.g., LAN, HDMI and SD Card reader) often continue to be recognised by the host iPad, some downstream USB devices are not recognised when connected to the hub.
By example, I have noted that while an Apple USB-C to 3.5mm Headphone Jack Adapter works as expected when directly connected to an iPad's USB-C port, it is now not recognised by the iPad when the Adapter is connected to a hub's downstream USB-C port.
Similarly, an ultrasonic microphone interface, connected to the hub via USB-C, works perfectly when directly connected to the iPad's USB-C port, but is now not recognised by the iPad when connected to a USB-C hub.
Prior to recent updates, both of the described devices worked perfectly when connected to the hub.
Given this change in established device support, it is a logical conclusion that something has changed in recent iPadOS updates. Whether or not this is an intentional but undocumented change in iPadOS device support - or is a bug - is currently unknown. As such, you would be best advised to submit a Bug Report via Apple's Product Feedback portal. For iPad and iPadOS:
Feedback - iPad - Apple
When submitting a Bug Report, ensure that you include details of your iPad model and installed version of iPadOS within the body-text of your report. Don't solely rely upon the pick-list - as this rarely includes the current versions.
NB: Every report counts. Until Apple receive a sufficient number of complaints/reports, they might not assign resources to investigate and resolve the issue.
