Vague regarding tariffs?? In what way. I have provided multiple examples of statements that "Customs duty relief will be removed. The current exemption from customs duty for goods valued at less than 150 euros will be abolished from March 1, 2028." That is a direct quote from the article. I thought it was a pretty clear statement. What do you find vague about it?

Here are more direct quotes:

"Platforms will become deemed importers. From March 1, 2028, platforms—instead of EU consumers—will be responsible for ensuring that customs duties and VAT are paid on the sales facilitated by them when goods are imported into the EU. The VAT and duties become due when the platform receives the payment for the goods, and the platforms need to include the customs duties and import VAT in the price at the point of sale.

EU customers will thus have transparency on the full cost of their online purchase and will pay for it in one go instead of being faced with hidden charges when their parcel arrives."

So, platforms, not buyers, are responsible for duty collection. That burden causes the "platform" extra expense.

"From 2025, VAT in the Digital Age extends the VAT liability of platforms, which will be made liable for charging and remitting the VAT when they facilitate a business-to-consumer and business-to-business sale of goods from a location in the EU. The fiction applies for both domestic and cross-border sales within the EU irrespective of where the seller is established.

Another important change relevant for platforms concerns the IOSS. The IOSS was introduced as an optional scheme for facilitating marketplaces in July 2021 and is proposed to become mandatory from Jan. 1, 2025. The ViDA proposal makes the use of the IOSS mandatory for platforms facilitating low-value imports into the EU."

"Platforms" are now responsible for collecting VAT.
The burden is on them. Using IOSS was optional. It is now mandatory. See Model Monkey's complaint about the burden of using it. So, there's your more expenses for the seller. This is creating more expense for both buyer and seller.