Hello and thanks to all of you for your help!
Terrypin, I thought about the player you mentione. I have a few in stock. But it's a minimalist solution, especially with regard to the organization and naming of MP3 files. It doesn't allow me to achieve my goal.
Sonofcy, of course I understand and agree with your comment. I use other developer forums on other platforms. The least I can say is that implementing preformatted text isn't very intuitive on the Arduino forum, I've tryed with no success(!)
Regarding implementing another solution, among the possible choices, I had selected a library using the VS1053 module.
I think I'll fall back on this library.
Vander_der_decken, I'm surprised that a library remains in the repository when it's obsolete; after all, it's a choice...
Thank you again to all of you for your help!