Even with external throat mics the vox detection is a second or more at least before transmitting. They work when using radio etiquette, call sign twice and mostly the throat mic doesn’t start until halfway through the first word not prior, whereas ptt (push to talk) allows you to switch to transmit before saying anything.
That’s just from my experience and i think throat mics have their place but for clarity and control over a transmission i prefer ptt.
I hope that gives you a better idea how they work and whether this is feasible for you or if you need to change any design ideas.