I’ve tried adding in an uhh on the first syllable. example: B’s are issue of mine. So butter. I usually block hard on the B sound. But if I focus on saying a little prolonged buhhh I can usually say utter after it. It’s not ideal but it doesn’t sound that unnatural D also. So like downhill. Duhhh downhill I can get it out. Might not work for everyone but it’s helped me to think about an easier way to say the first syllable of the word in a different way