I'm applying to Ph.D. admissions in the US for Fall 2022 and need to obtain the third LoR. I have two choices:
My undergraduate college professor, with whom I've collaborated extensively for about a year. The professor was also the supervisor of my bachelor's thesis. The professor wants me to draft the LoR, and will sign and send the same. I tried to convince the writer to write based on points provided by me but was refused - either I write it myself or don't get it. However, my achievements in collaboration with this writer are significant, including a first-author paper and a national honor.
A researcher, with whom I've only collaborated for about two months. The project is ongoing, and no papers have been written yet. However, the writer will be drafting the letter, though it will probably be weaker.
Which would be the better choice, if I'm applying to some of the top universities in my field?