Is it valid for me to lead prayer if I cannot pronounce Ra correctly?

Assalamu Alaikum I am a Hafiz Alhamdulillah, but I have problem pronouncing the Ra sound. There is a joint below the tip of my tongue, which makes my tongue tip-less and I cannot make the Ra sound. Whenever I try to pronounce Ra, the sound of Waw comes out. I have tried a lot of time when I was small, and when I was doing Hifz but it did not improve. Now since I am a Hafiz, I am usually asked to lead the prayer when the Imam is not present in the Masjid. I want to ask whether it is ok if I lead the prayer? I cannot even pronounce Allahu Akbar properly. The sound comes out as Allahu Akbaw, but people usually don’t notice. And then there will be many more mistakes in Surah Fatihah. So is my prayer valid? And what about the prayer of those who are praying behind me? I heard one ‘Alim say that if Takbeere Tahreema is not proper, then a person will not even enter into the prayer. It is as if he has not started the prayer at all. What should I do then? I cannot pronounce it properly. I hope Allah will accept my prayer because I am ma’zoor, but if I am leading the prayer, will the prayer of those behind me be valid? Jazakallah Khair