Saw two interesting products from NAB 2019 on YouTube that seems really awesome The first is the Rode Wireless Go wireless audio transmitter and receiver: https://www.rode.com/wirelessgo It seems really, really lightweight and easy to use. NoFilmSchool featured it: It seems perfect to dip one's toes in the world of wireless lavaliers systems. The clip on transmitter includes a mic element (or one can use a regular lavalier mic.). The video showed it being used with an iPhone although they need TRS to TRRS cable and the Apple headphone adapter? The other interesting product is Filmic Audio? (Mentioned near end of the video) It appears you can use an extra iPhone running the app to record audio.. and then it can pair and replace the audio on the Filmic Pro footage. THAT seems pretty interesting. Put your old iPhones to use.
But alas, my older Apple gear does not record in stereo. But I do have a Zoom H1n. I have tried different ways to get that thing mounted on MCR without really being in the way.
It probably depends on what kind of audio you're recording. For an interview situation where you might want to use a lavalier, you could get a small recorder and a wired lav, and have the interviewee put the recorder near them, like in a pocket, or maybe even gaff taped to their back --- don't laugh: a friend who's a guitarist taped a portable recorder to his thigh for an outdoor shoot, and the sound was surprisingly usable. For example, a Zoom H1N and a Rode Lav+ would be a nice setup that's easy to hide. Then just sync in post with your phone's sound recording or by watching their lips.
I am PUMPED about the Rode Wireless Go system!!! Definitely on my shortlist of gear to acquire. I currently just use audio from the phone and looking for an upgrade. I almost bought a ZOOM until I saw Rode's NAB annoucement.