Help needed: can't install new Android extensions

Whenever I try to install an Android extension, except for the Recommended ones, by pressing "Add to firefox", I'm prompted to download the .xpi file and when it finishes I press " Open file" but I get an error saying I don't have any app which can open those files.

Has this happened to anyone else? Does anyone know how to fix it?

I'm on Mull 120.1.0