iPhone video - audio out of sync

Hi, I've started using Rush to edit travel footage from my iPhone 12 Pro and GoPro Hero (4 and 11).

On the iPhone footage I found that upon import the audio and video are out of sync.

I've googled this and the a few post from a few years ago say this is a known problem with variable frame rate in smartphone footage.

one suggested solution is to transcode it on something like Handbrake to get a constant frame rate.

that works as a workaround if you edit on laptops.

but if you edit direct on mobile / iPad, what's the solution that isn't desktop software based?

thanks for your help!