My understanding is that for China and a few other countries, the De Minimis is being replaced by an enhanced "type 11" process. This process lets one import items with values up to $2500 USD in a streamlined process. Exporter/seller has to follow the "enhanced" custom's steps where the seller has to pre-register with Customs the item/s being imported. Seller's name/business, Purchaser's name and address, the full 10 digit commodity code, Item/s value, and then pay up front associated tariffs and processing fees. This way it makes it look like the seller is paying all the tariffs, but in reality, the seller has to collect the tariffs from the buyer and then pay this to Customs. If the Tariffs aren't paid, then the buyer must pay the bill before the item clears customs.
My understanding is that it is a similar process to how sellers in other state's like E-bay, online shops, and Amazon have to collect sales taxes for the states they ship their items to.
I presume that this burden will fall on Aliexpress, Temu, and other foreign online sellers.
Through this process, if tariff rates and policies change, Customs will charge and collect the Tariff-de-jour. For all of us who used the De Minimis process, those days are gone forever.