theres definitely ways to learn to alter your speech quality, tho im not exactly an expert on the methods. i would recommend looking into the articulaters to start, to get an idea of what moves to make which sounds. a lot of the articulation is subconscious so we dont always realize what we're moving until we put a label to it, and becoming aware of each part and how its behaving it can give you an idea of how to start practicing different speech qualities
even if you cant find someone to work with right now, it might still be good to start reading into articulatory phonetics! if you have the time and energy for it, having a baseline understanding of the speech structures and how they manipulate sound is really important to speech therapy in general. hopefully you find someone to help you out! that sounds really stressful so its good in this case to stay in your comfort zone