You are greatly underestimating the sound quality from the APP’s.
First, regarding your earlier comment, AAC at the level supported is effectively transparent. Quite likely impossible for anyone to reliably tell the difference from the source.
Second, the APP’s are in an entirely different league sound-wise than the wired Apple buds. Not even close.
Third, the APP’s are closer to an in-ear-monitor than an earbud. IEM’s produce different sound than over-ear headphones, but are capable of being extremely high end. Most serious headphone enthusiasts use some form of IEM for their portable listening, and have done so for decades.
Personally, I’ve been seriously into headphones for more than 20 years, and have several pairs of thousand-dollar plus models in my collection. The APP’s are actually a really good sounding headphone, even in comparison with my best stuff. As usual, when Apple takes sound seriously, they get it right (see the essentially flat output of iPods, iPhones, etc. for years, the phenomenal amp/DAC in their lightning to 3.5mm adapter, at an unbelievable size and price, the HomePod, etc. etc.). I’m fairly sure I would prefer the sound of the APP’s vs. $80 AKG’s as I still choose to listen to them over my previous work cans which cost many times that.
As for the original question, the main strength of the APP’s sound-wise is their mid-range. They are top-tier there. The highs are their weakest - they can sound a bit rough at times - but by most people’s standards they are still well above what they are used to - certainly miles above the output of the speakers on an iPhone or MacBook. You should enjoy them very well. 👍