U.S President Biden has been in the news, such as this article in Forth Worth Star-Telegram, appealing for tougher gun laws. The article says that
He repeated calls to restore a ban on the sale of assault-style weapons and high-capacity magazines — and said if Congress won't embrace all of his proposals, it must at least find compromises like keeping firearms from those with mental health issues or raising the age to buy assault-style weapons from 18 to 21.
Yet in other news we hear that he has signed an executive order legislating something or other (the executive orders signed by President Biden can be found here in the Federal Register).
This article at the National Constitution Center says that
An executive order is a directive from the President that has much of the same power as a federal law.
Question: So instead of begging for support for his wishes on gun control, why can he not simply legislate that through executive order?