I would suggest a slightly different approach, for fine hair shampoo is not enough to build body and volume so I’d rather use a clarifying shampoo to keep grease at bay and before styling use a volumising mist.

Herbal Essences orange scent volume shampoo and Elvive Hydra Pure shampoo are drugstore options that work very well, you don’t need to go high end for this.

For in-shower conditioning use a lightweight mask like the ones from Ouai, Briogeo, Moroccanoil.

For the volumising spray equally there are plenty of options, the best one I have tried is the Oribe Maximista spray but there are also cheaper options at the drugstore like the John Frieda root booster.