First of all. I'm not an expert and have been doing photography only 4/5 years. But like to express my own opinion with others and expect same from others.
I don't use RAW because it takes a lot of space in my card ðŸ’³. I usually captured 150/200 pictures in my weekend, so it's not my friendly opinion. I always use JPEG and get quite well details in my pictures. Don't use AUTO Mode and play with exposure ;I'm sure you will find more options. Wildlife photography is really tough, I can see, mainly when I'm going to capture small birds in its natural habitat. I'm not sure why you aren't getting good details and lot of noise. Use f/8 when you are capturing bird with our low budget 150-600mm Tamron.
Have a nice Sunday
Slaty headed Parakeet (9)