Personally, I think that bitcoin won't become a new world currency like USD or EURO,
Why BTC would become a stable coin like USD and EURO, I know countries tend to choose a currency that would be less volatile and has a better future which BTC lacks but the idea of comparing them with USD and EURO is scary like the volatility of BTC is what that attracts people.
will create a huge load on the bitcoin network to make all these transactions
Yeah, I admit that the Blockchain of BTC can process a maximum of 7 transactions in one second and there is more than 7 million population in EL-Salvador (taken as an example). If all of that citizens make a transaction then it would take around 10 days to process those transactions. Which is not reliable. So yes BTC needs upgradation before making it a currency of reserve.
will dump the price of BTC as well.
Yeah, one more thing is pump and dump schemes are not only applicable to BTC (which i just came to know about few days back by making a topic of
Is Bitcoin truly free of Pump and Dump Schemes? USD and Euro which are used as reserves for countries are also prey to these P&D schemes. so overall, your points are legit, and honestly very bitter truth about the adoption of BTC as Reserve currency.