I don’t know of a way of doing this with the volume curve by selecting on the clips, that sounds pretty fancy. Are you wanting to cut up the regions at the breaths and then select all of them and then have it turn down the level but 10dB or something?
You might already know about these but just in case
iZotope RX 7 standard has an edit process for this and you can round trip in Cubase with the Direct Offline Processor (not working for me on a Mac in Cubase 10.5 currently)
There is also Waves DeBreath (right now 12/28/2019 it’s the cheapest I have seen a Waves plug-in at $25.00)