It would be great if NothingOS supported https://github.com/kavishdevar/librepods without root, this adds another incentive for iPhone users to switch to Nothing over other OEMs if they don't lose the "it just works" in Apple's ecosystem. OxygenOS and ColorOS 16 already has fixed this, making the app work on their phones without root.
This is the workaround- bypassing the l2c_fcr_chk_chan_modes function. I don't know how oppo/oneplus has done in their skins, but maybe my workaround under developer options should suffice and wouldn't require much digging into the actual problem.