Not true for the Poco F1 (although AFAIK you still need to build your own kernel on postmarketOS to enjoy this): https://fosstodon.org/@joelselvaraj/112621744555315631

Shift6mq is supposedly close, with OnePlus6(T) its more difficult due to I think the way the sensor is connected.

Currently, the Pixel 3a is the most promising device in terms of Camera Support on a Qualcomm device with mainline kernel from what I can gather.