Is it permissible not to deliver the currency earned in forex trading (Euro) and instead receive another currency (US Dollar), knowing that delivery in US Dollars is based on the value of the profit from the earned currency and is mandatory?

For Forex trading to be permissible, it is a condition that leverage not be used, because it is a loan, and it is not permissible to stipulate brokerage fees on a loan. Furthermore, in buying currencies, gold, or silver, it is a condition that the exchange takes place on the spot, meaning that the euro, for example, enters your account in such a way that you can dispose of it. If the broker records your profit in dollars, this is an indication that the euro did not enter your account, thus nullifying the transaction, based on the Prophet, peace and blessings be upon him, who said: "Gold for gold... hand to hand." Monetary currencies are subject to the same rulings as gold and silver.