For adding water pressure to the shower, you can look for something called "high pressure shower head" on the market. As its name says, it is different from ordinary shower heads in that it can increase water pressure. Sorry, I don't know the specific principle. After I replaced such a shower head, my shower improved greatly, and the water flow no longer crawled slowly over my back. This saved me a lot of time.
You mean the Ecocamel which draws air in up the handle so gives the felling of a better shower with using more water.