If you want to use a mobile boarding pass, I can't think of an alternative, unless perhaps if you use an Apple computer maybe there is some way to get the boarding pass into your Apple Wallet. I don't use other Apple stuff other than my iPhone, an Apple Watch, and an iPad, so I don't know since I'm a PC user. Maybe I could finagle it using Apple Photos or Files through a PC, but I've never tried that, or possibly something with Google Drive through a PC or Mac.