I just received my iPhone 16e (running iOS version 18.5) last week and I'm experiencing the Bluetooth stuttering issue as well. Sometimes the phone will disconnect completely from my vehicle/Apple Carplay. Other times the audio will pause, drop out, skip, etc.,.. This occurs with different vehicles (Jeep Wrangler, Infiniti Q60, and Ford F-150).
The bluetooth stuttering also happens with my Beats earbuds as well.
I haven't observed any disconnects with my Apple Watch Ultra 2, but I'm sure that could also be taking place without my awareness.
This did not happen with my prior iPhone or my Samsung devices.
The carrier (AT&T) can't do anything for me (aside from a network reset, which did not provide resolution). They stated that they are adding the issue to a 'watch list' for trending issues/problems.