Do terrible MYP 4 and 5 affect US university admissions that much?

Hypothetically speaking, if one has a super high predicted (e.g. 43/45 with rigorous HLs), but rather mediocre MYP (around 4/5's for the best fit), would it affect US university admissions THAT much?

I do know that they appreciate an upward trend, but the thought that my poor freshman and sophomore years could be a declining factor. Would an appropriate reason for the negligence (like bullying, new school environment, family etc) cancel the poor MYP?

The worry of this is still haunting me ngl.