What defines a "strong" currency is it's devaluing rate, not the exchange rate per se. The Peso didn't get stronger because of how the central bank sells dollars. Think about it: if that was to be the case, last year the Peso should have been 3 times stronger than it's now, because the dollar was 3 times cheaper than now (right before the elections). So how is it that now the dollar is 3 times more expensive yet the Peso got stronger than ever? Because money emission was shut down.

Now, right after money emission was shut down, there's still an inertia effect in the market: merchants simply know that next month the dollar will be more expensive and then everything will be more expensive, and if you don't update prices accordingly in time, you go bankrupt next month, because you will not be able to restock for it will be more expensive than the price you sold stock the month prior. And so on. In a context of non-stop emission, that prediction is always right. Now, when emission stops, who will be the first one to stop incrementing prices? Will my provider stop? Will my provider's provider stop? Will my provider's provider's provider stop? I don't know, I can't take the risk. Everyone will think the same, and as the "prisoners dilemma" states, for some months, I will be indeed right in my fear. This inertia can last up to a year or two, for there's a delay between the monetary base change and the inflation index impact it has, as Milton Friedman noted, and as it's being our case, thus empirically demonstrated (once again).

And it's indeed a good thing that inflationary inertia is fading slowly. Can you imagine if all of a sudden prices correct to actual index? Everything is twice as much expensive all of a sudden: no one can restock, commerces go bankrupt by the minute, no family can afford anything and nothing can be bought from nowhere because everyone went bankrupt thus goods are getting scarcer by the minute and thus more expensive and so on. That's indeed the hyperinflationary death spiral that was menacing the economy and that was so carefully dismantled.

So, now we understand that there's an inflationary inertia that must fade smoothly, giving time to everyone to sync. But... to what value? ...there's no more inflation, ok... what's the final ARS/USD rate? ... since in the very process of undoing it's monetary control policy the government can control said smoothing effect, then it aimed for a rate as close as the one the ARS/USD soared to at first in the black market in the initial months, which is currently set at 1500 ARS/USD by the end of MIlei's term. Which is indeed the worst price it got to in his first months. That's a psychological choice, because it's the value people already saw, so it's the safest to aim for. Now, how so? By stopping inflation, policies tending to suck pesos from M0 create immediate scarcity which pressured the dollar downwards. Dollars from exports, renegotiated debt, and foreign investment cause a surplus that pushes the dollar price (in the black market) down even further. As you can see in the curve of the historic price chart, at some point it even reached the official price. Direct intervention was used to avoid panic bank runs like the one that happened in the middle of the year, which would have caused temporal noises that would have disrupted the smooth transition, potentially causing bankruptcies and social distress. That noise-suppression policy will continue until the economy can be dollarized, but for that enough dollars are needed, so the government is aiming to a final 1500 ARS/USD rate (worst case scenario, optimistic is 1200) based on the assumption that this path will ensure enough dollars will be available to dollarize at that rate in a couple of years.

Before energy exports, foreign investment and renegotiated credit at lower rates was possible, we only had debts and a net negative balance in the central bank, so the actual rate if things where to be updated from day one would have been 3500 ARS/USD in the most optimistic scenario. That would have caused an inflationary spike of 300% in a matter of HOURS. Try to picture the consequences.

Finally: you need to sell cheap to be competitive, not ruin the entire economy. No economy works like that. You might get a temporal advantage by devaluing the currency but no successful country was created that way. Devaluing the currency is never, absolutely never done to "create an economic advantage". That's just the way corrupt governments like disguise as good intentions the act of stealing from peple via emission. Devaluing is never good, in no context. Conversely, every country with a sound economy haves a stable enough currency, or even an increasingly valuing one.