missing-root The audio input and output for the analog audio jack was always very low quality due to never having a high end DAC. There's still wired headphone support via USB-C. Even the basic Apple and Google USB-C DAC provide far high quality audio.
USB-C headphones are fully compatible with our USB-C port control feature with the default Charging-only while locked node. It allows the existing connection to continue while locked but disables new USB connections immediately and then fully disables USB when the headphones are disconnected. It does reduce security compared to not using it through keeping USB data partially active after locking while it's in use, but only while in use and data is fully disabled immediately as soon as it's unplugged. New connections are also blocked immediately after locking including at a hardware level, not just a software level. The USB-C controller in Pixels supports blocking the new connections at a hardware level while keeping existing connections working and has disabling data completely as a separate thing we can do once the existing connections end. It also has the option to fully disable it for even charging, which is quite useful since USB-PD isn't simple.
Analog audio jacks going away is simply something you're going to have to accept as part of devices becoming more modern in the same way that laptops rarely have an Ethernet port anymore despite that being more secure than exposing Wi-Fi attack surface. Phones also don't have Ethernet ports but you can still use Ethernet if you really want to via USB-C in the same way you can still use wired headphones. Dedicated charging ports on laptops are also going away and being replaced by USB-C charging. USB-C technically supports up to 240W power being supplied... Dedicated display outputs are also being replaced with USB-C via DisplayPort alternate mode. This is simply how things are going. Eventually there will probably be no ports on devices... By then, hopefully all the firmware and driver code is in a memory safe language combined with far better exploit mitigations and fuzzing, etc.