My university students are often, at least at first, quite timid about playing loudly. (This is probably a side effect of learning the instrument in a school band program. They learn to play quietly because their section is too loud. Or, they get the hand from a band director who doesn’t have the time or bandwidth to correct tone production issues.)
When I push them in lessons to play with soloist-level dynamic range, they often give me a weak mezzo forte instead of the fortissimo I’m looking for. The more I ask for volume, the more they dig in at an unimpressive medium-ish.
At this point I usually ask what they think would go wrong if they played louder. The consensus seems to be that it would sound “bad,” in ways that they generally can’t quite pin down.
So I give them permission to play so loud that something goes wrong. Then they usually find some volume they have been holding in reserve, but still fall short of what they are capable of. I usually have to insist more and more firmly that they play louder and louder to show me what will go wrong.
And, virtually all the time, nothing goes wrong. They find some more available volume, and probably a fuller tone to go with it. If I’m lucky, they learn the lesson and feel less timid about volume in the future.
The issue does often come back when we encounter something new, unfamiliar, or stressful, like a complicated ornament or a note outside their comfortable range. In those cases, I have to remind them to go ahead and put air into the instrument, and to allow whatever bad thing they are dreading to go ahead and happen. If it does (and it usually doesn’t), we can hear it and troubleshoot it. But sabotaging themselves by choking off the air just guarantees failure.
Use your air confidently and powerfully. You might discover that what you have been worrying about isn’t a problem at all.