According to a CNBC article that cites this source:
https://www.congress.gov/crs-product/R48549#_Ref196320321 states that Trump ended de minimis using the IEEPA, though the Supreme Court ruling makes no mention of de minimis.
In any case, effective July 1, 2027 the “Big Beautiful Bill” will repeal the basis for de minimis exemptions that exists under the US Tariff Act of 1930. The Trump admin has specifically targeted de minimis as a vector for fentanyl being shipped to the US:
https://www.whitehouse.gov/fact-she...-exemption-for-commercial-shipments-globally/