When you buy licence, you can use the licenced asset according to the licensing terms which include only a few restrictions. This is true for any licence type.
An extended licence will allow you to put the asset on mugs, t-shirts or posters or similar and to sell those. There's no difference between a modified or unmodified asset in this sense.
Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788 (Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).
ABAMBO | Hard- and Software Engineer | Photographer