Differentiating subtle differences in SQ between exact same source masters in different codecs usually requires a detected audiophile with some training and very intense and patient listening. Almost never applies to casual iPhone listeniI can definitely hear the difference especially on older music where there are isolated channels, what I can only call the ambience of the music gets thrown into the bit bucket
Probably not what you are looking for, but consider a third party music app that lets you add your lossless files directly into the app.