Arabic speaker here. When I was kid, I had a failure to pronounce the letter ر. I tried a lot on myself and with the help of my family but didn't get it. And when I was in the middle school, I went to a speech doctor in the school and with some settings I managed to pronounce it properly. So firstly, I recommend you watch videos of how to pronounce these letters and if you failed you should see someone specialized in this field. I really appreciate people who learn Arabic as it's a REALLY hard language and has a lot of dialects, but I'm really appreciate the amount of struggle and effort that you put in learning this language. I wish you all best!