With hard to say words, do you exaggerate or say them softly?

With hard to say words, do you exaggerate or say them softly? I probably need to stretch out and open my mouth bigger when I speak in general. I am quite self conscious of my mouth when I speak causing me to speak using my lips. But the thing is I am learning a language and there are words that without eye contact I can say fine but if I look someone in the eye and say, it’ll come out like a stutter. I’ve tried saying them softly while stretching it out and will still stutter. But when I exaggerate the words by opening my mouth bigger while stretching the sound, I don’t stutter. But it feels like I have really slow down and exert a lot of effort in opening my mouth. It almost feels too slow to me. But when I record it myself, I sound fine. I’m feeling quite down because there are some words I want to say effortlessly.. but it almost feels like tiring when I exaggerate.. Thoughts?