How do I get to listen to my previous iTunes purchased music on iMac?

Dear Community/Apple, I have been happily using my old iPOD Nano for Years, however it now has to be retired and I thought that I would transfer all my music onto my Phone and listen to my collection there. Note it's an Android phone not iPhone. Most of my collection has copied across without any problems, however I have 12 remaining tracks that I own and paid for that I can no longer listen to because according to this site and similar questions they are Protected M4P files, which would need to be converted to a new format M4A (which is what my other owned, paid for tracks are). Following recommendations found in the community I removed four of the tracks and downloaded again, however have ended up paying for music I paid for Years ago and had been listening to happily on my iPOD... Please can someone tell me how I can convert the remainder of my collection, 12 tracks, which are M4P to something I can play upon my phone without having to pay for a subscription of some app to convert it.....

[Re-Titled By Moderator]