Hi ! I would be interested in building your prototype for you !
I have launched a few apps in the past (not marketplaces but some things quite similar) (you can take a look at hatcher.fr for example)
and I have been teaching bubble for over a year and a half now. I also published two plugins you can find in the store (New plugin ! A customizable slider input and the Easier Dark Mode plugin. Moreover, my main ability with bubble is to do things really fast, and I often design prototypes of website for friends.
Do you have a idea of the complexity of your prototype ? And what is your budget for the developement ?
Anyway, it would be a pleasure to work with you and good luck for your project !