I don’t want to lose my sick voice!

Help! Usually my voice is very nasally and annoying to listen to. However, I have noticed that when I get sick (usually with the flu or Covid), my voice turns from “Ira Glass meets Eric Cartman” to “Sam Elliott.” No kidding, best impression of my life I sound exactly like him. I also work on the phones for the living, and in the financial services industry. I often meet new clients through referral, and introduce myself on the phone. I believe that this voice is much more commanding, and would likely net substantially better results.

How can I keep this voice after I recover from the flu?

I even made a Reddit account to ask this question. Hoping you all can help.