So overall I did enjoy this film, moreso than Rocky (I), the only prior film in the series I've seen. A lot of talk about how it reversed the focus on race from the slightly problematic great white hope versus uppity black man dynamic...but since I didn't really have that hit me watching the first one, that contrast didn't stand out. It does perhaps get into the "acting white" burden, the fear of inauthenticity in the boxing community and the black community if there is the appearance that you didn't earn it through hardship. And that it is tricky when the unit of measure in the community is something like sports rather than academic driven pursuits.
If I am at all conflicted, it is in how the story of Rocky's cancer plays out. I was touched by his talk about how he saw his wife go through cancer and how bad the treatment was for her, and ultimately ineffective. I thought it was a really strong statement in favor of Hospice and against the presumption of it always being best to go full out to fight. So when a big part of the final third is Rocky being inspired to fight through, contrary to his prior statement, and writing it all off to depression/loneliness I think risks selling real end of life questions short. It isn't really a this or that question anyway, he can choose to embrace Don as family and find meaning while also choosing not to fight the cancer full-bore. Life expectancy isn't actually particularly lower for those who choose less aggressive approaches.
As to Don' chief rival...good thing he turned out to be an Everton fan, if he'd been a Liverpool fan I might have had to cheer for him instead of Don.