Leclerc’s engine was so old and worn down by Abu Dhabi that it barely even worked. Even if they had better engine modes available they wouldn’t have been able to use them since the engine was already on the verge of failing. (Which is why he had to take penalties)
Leclerc was already losing several tenths per lap to Sainz in Las Vegas due to a lack of engine power.
You can ”turn up” a fresh engine by picking a higher engine mode before it gets locked in Q1. But if the engine can’t cope with such an engine mode out of reliability concerns you have to live with poor performance.
Also I consider it unlikely that there will be any significant reliability upgrades for 2025. The engine is already great and I don’t think Ferrari is willing to invest the money required to make the 2022 engine modes work reliably when there is an engine development budget cap in place.