To be honest, El Salvador's announcement of Bitcoin as a fiat has no effect except for the residents of their country. In terms of price, the price of Bitcoin still fluctuates between US$30,000 and US$40,000, which is not even as big as Musk's Twitter. For miners, mines are more inclined to be established in places with a stable political environment, and El Salvador obviously does not meet the conditions. For this reason, El Salvador will not occupy a high hash rate.
However, El Salvador is a symbol, and Bitcoin can be used as a symbol of fiat. This is an important step in the development of Bitcoin, but it will not affect Bitcoin's position in today's world.
We never know if your speculation is going to be true, remember that things might turn around for El Salvador now that bitcoin is a legal tender plus it's not yet a month that they made it a legal tender so probably they are taking things at a really slow approach.