Going to 7500 feet from sea level without acclimatization means that on average you will be losing around 15% off your normal aerobic power. So for a given RPE or HR, your power output will be about 15% lower. With full acclimatization, you’re typically only down 10% at that altitude instead of 15%.
7500 feet is low enough however that you’re unlikely to be at risk of developing any altitude sickness, so the role of acclimatization for that purpose is minimal. Conversely, this also means that it is less likely you will suffer some of the adverse effects of being at altitude for the first few days, that may impair performance (sleep impairment, etc.), so the harms of going up a few days ahead of time are also less than if you’re going up north of 10,000 feet.
The physiological adaptations that occur during acclimatization to hypobaric hypoxemia are not really replicable by doing other types of training. There is no getting around the fact that at 7500 feet, barometric pressure and the amount of oxygen available for you to breath in the air around you, is 25% lower than at sea level. And as a result, the amount of oxygen in your blood will be lower (typical SpO2 at 7500 feet would be around 88%, instead of ~100% at sea level).
Acetazolamide, while useful to help promote acclimitization and avoid altitude sickness, does not improve endurance performance at altitude in unacclimatized people.
Basically, if you can get up there like ~two weeks before hand and sleep at altitude, you’ll be down 10%. If you show up the day of, you’ll be down 15%. If you show up even a few days before hand, you may partially acclimate, and end up somewhere between 10-15% down. However, you may want to try sleeping at that altitude beforehand to make sure that you don’t have issues with sleep. If so, you may be best to either show up the day of, or well beforehand.
If you go up at least a few days before hand, avoid alcohol, drink enough water, eat lots of carbs, and avoid overly strenuous exercise - these will all help you acclimatize a bit faster.