iPhone 14 Pro Sound Issue

When iPhone 14 Pro is connected to my stereo system via a 3.5mm adapter to use my stero speakers as the sound output with no headphones connected, the volume is noticeable lower than with my Xs phone. Believe it may be recognizing the input as headphones and that may be why the volume is being restricted even though I have the headphone volume limit turned off and not using headphones. I have tried to change the volume via the control center to no avail - it is turned up all the way. I tried connecting it via blue tooth and the volume is still being restricted. In theory there should be no reason why the volume is being restricted when connected via blue tooth in order to use my phone like an iPod device to play my music without headphones through stereo speakers. I noticed that even in that mode - when connected to blue tooth, the headphone icon shows up in status bar. Any help would be greatly appreciated!