I am using the developer betas and sending them feedback constantly about the issue.
The most annoying part is that even the default ringtones like “Opening” will crackle a bit at maximum volume from the earpiece.
To replicate the issue even better, go on YouTube and listen some piano music at maximum volume, it will crackle horribly.
Yes, the issue was present on iPhone 8 Plus also and was fixed with a software update and the same could be done on our XS’s if Apple will realize this is a widespread issue.
They just need to tone down a certain frequency and it won’t affect the maximum volume at all.
If enough people will provide feedback to Apple, i’m certain this will be sorted quickly.