David Giovannoni has recently created a new website https://i78s.org/ which contains over 46,000 early recordings 1890s-1930s, mainly from USA sources. Its free, but you will have to set up an account to access the recordings. Searching for 'concertina' gives you eleven cylinder recordings, nine from Alexander Prince (Maccann duet), and two from Isak Piroshnikoff (English). I think you will be surprised by the quality of these cylinder recordings compared to the more common 78rpm records.
David was responsible for discovering, and transfering to audio for the first time, the earliest known recordings from the 1850s made in Paris by Leon Scott de Martinville on lampblack-sheets.