There is a Polish accordion forum site. They dont use a better software but they are well organized. Polish people loves accordion. In Polish unfortunately but doesnt matter much in these days, you may use with auto translations. I was also active there, there are many good free Polish and other sheet music available. You may even learn some Polish like myself
The Forum:
https://forum.akordeonowe.pl
Free Sheet Music:
https://forum.akordeonowe.pl/darmowe-nuty-akordeonowe/
The Forum:
https://forum.akordeonowe.pl
Free Sheet Music:
https://forum.akordeonowe.pl/darmowe-nuty-akordeonowe/