[self drafted] First timer here, need help drafting sleeves for a t-shirt Sewing Machines Parts and Sales in Los Angeles

I worked on my first t-shirt a few weeks ago. The result was not so bad but as you can see in the pictures, the sleeves are not properly sized. The body fits perfectly without the sleeves, but then I undid the side stitch, and added the sleeves, and the shoulders ended up too tight and this happened

Here is a picture of the pattern I drafted from an existing t-shirt. Here is sleeve attempt 1 and sleeve attempt 2. The first attempt I just followed the curve of the sleeve opening on the body and added the sleeve by measuring the lengths, but that curved shape does not look right. The bell shape in the second attempt looks more like what I’ve seen elsewhere but was still too small for the sleeve hole on the body.

Now, my question is, how do I draft sleeves from an existing t-shirt? I’ve tried following tutorials, and the arm length seems fine, but I can’t seem to get the circumference of the seam correct. I’ve just drafted a second pattern and have already stitched the shoulders together and really need help with making the sleeves. I can’t seem to understand how that bell shape is made and how it properly fits in the curve that’s clearly not a bell shape!

Thanks!