If there's one thing consistent with DMR it is inconsistent audio levels

There is one DMR radio notorious for super hot mic gain right out of the box and that is the AnyTone 578 mobiles, setting the mic gain to 1 is still way too hot for most users.

Improper mic gain settings on digital will result in horrible audio way too loud or too low, high audio causing clipping and distortion
If you're too close to the mic people will hear you huffing and puffin breathing and spitting, it sounds horrible and you will run into this all the time.
To avoid sounding like crap adjust your mic gain to the lowest setting and use the parrot or test it with a friend on a TAC channel.
Set your receive volume to a comfortable level and listen to yourself and see if you like the audio quality.
If you can pass your fist between your lips and the radios mic that's a perfect distance, talk in a normal tone and don't yell, its not HF you're not trying to modulate a signal on DMR.

Unfortunately not everyone is going to know they sound like crap and there will be times when someone pops in there so loud the speaker on your HT will vibrate and move across your desk and hit the floor.
Telling someone they sound bad with horrible audio ("Audio Shaming")  is like telling someone they have bad breath, you have to be careful how you approach the subject, some may be appreciative and thank you for the observation while others will take offense and get all butt hurt. In any case you are the auto audio leveler with your fingers on the volume knob.

Turn down the mic gain
stay away from the mic
don't breath into the mic
speak in a normal voice tone
keep your receive volume around 12 o-clock or less when testing
USE THE PARROT TG:9990 it's there for this reason
be ready for that one guy who is super loud.

Don't be that guy who sounds like crap, nobody will answer your call if your way too loud