Is money earned from working in email marketing, which involves promoting various offers, some of which may contain an element of deception towards customers (even if the promotion of suspicious offers has ceased), permissible? And what is the Sharia advice regarding this matter?

There is no objection to the aforementioned work as long as the offers are permissible, and there is no fraud, deception, or promotion of forbidden things. Your not knowing what will happen with the customer does not affect the permissibility of the work or what you earn from it. However, taking 3% of the profits in addition to the monthly salary leads to ambiguity in the commission, and the original principle is that the wage must be known. The majority of scholars hold that it should be a fixed amount, while some scholars believe it can be a percentage of the profit. A narration from Ahmad states the permissibility of combining a fixed amount and a percentage of the profit. It is better for it to be either a salary only or a percentage of the profit only, to avoid the issue of combining them. It must be noted that the contracts of most insurance companies are forbidden because they involve gharar (excessive uncertainty) and riba (usury). Therefore, it is not permissible to promote anything other than Islamic Takaful insurance. Care must be taken when promoting programs that might involve forbidden elements.