alarm ringer low after first ring loud

The alarm on my iphone 14 pro does not ring loud after the first ring. The rest ringer is low despite I have the volume high. Alarm rings loud only first time that start ring. Please note the same happens when my phone accept a call, the first time rings loud after that the ringer is very low. Please note I have syncronised it with my apple iwatch8. Could you please help how to solve this problem?