Renée Zellweger won the Best Actress Oscar. But that was it, Oscarwise. (Just one other nomination for "Best Achievement in Makeup and Hairstyling". Zzz.)
The main thread is the 1969 version of Judy Garland. She's kind of a mess in every way: broke, abuser of many substances, a number of failed marriages. But she still has her singing voice and showbiz talent, wowing them in Westminster. When she can shake her bad habits long enough to show up.
And, as a closing title at the end reminds us, she was only a few months away from an untimely OD death.
There are flashbacks to Judy's Wizard of Oz days, where (apparently) her problems began with psychological abuse from Louis B. Mayer, and a steady supply of diet pills from studio handlers. (Can't have a fat actress!)
While admiring Ms. Zellweger's talent, it wasn't enough to make the movie even vaguely interesting for me. Talented performer succumbs to inner demons—so why should I care? Your mileage may vary.