Some years ago I bought a programa Tabledit(€50) and with that program you can put music on paper by notation or tablature for many instruments.
One of those instruments is the diatonic accordions and also the Cajun-accordion.
From the start I'm busy with putting Cajun-songs in Tabledit.
The maker of the program also made a free program TEFview, just like Tabledit available for Windows, Apple en Android and you can play the songs made with Tabledit.
The files have the extension .TEF and you can find them on the internet te for many of the instruments which can be edited with Tabledit.
With TEFview you only can listen or look at the files, but you can slowdowns the music, so it's easier to play along.
Download TEFview with this link.
You can find the files I made until now on this pagina
The files also are on the website Freetabs.org, and there is much more for other instruments en music.