I picked up a Rode AI-Micro based on Stone262’s recommendation in this thread…
Although it’s for mic level, all you need to do is reduce the in-gain level and it works perfectly for line level signals, so you shouldn’t have any issues with your gain. It also works in the Apple camera video app, and Rode’s own apps (which are perfect for video and audio recs), and I presume any other video app on the Apple phone. For £60 you can’t go wrong, and you don’t need the Apple camera connector either. I just just use the line level out from my mixer/device rather than USB.
Uuoff err no idea! Can’t say I’ve thought to try. I just use it as recording sketch pad when I can’t or too lazy to turn on the studio. I used just record straight into the standard voice memos app then found worked in GB.