Ceteris paribas, is a student with consistent excellent grades preferred over one with a steep upward academic slope.
Besides playoff contending baseball teams in August, I cannot think of ANY circumstance where the latter is preferred over the former.
Consistent excellent grades.
Exception: if the low grades were caused by homelessness or other significant disruption in life. (“I was immature”, “my teacher was a harsh grader”, etc, don’t count at all).
Colleges will always prefer consistent excellent grades.
However, a strong upward trend is certainly better than middling grades throughout HS, and certainly better than a down trend.