Can I sell the same product FBA and self-fulfilled to see which works better?

I’ve been gearing up to do FBA for a few months now. Doing research, setting up my account, getting product made. A month or so ago, I joined Etsy to test it out too, and it has kind of gotten me thinking I can handle the self-fulfillment gig.

There are obviously pros and cons to both, but I want to test which works best for my budget and lifestyle.

Is there any way to sell the same product on Amazon via FBA and at the same time, self-fulfilled? For example, I could send an inventory of 20 items to Amazon, and keep 20 at home. Not sure if the seller could switch to how they want to do it, or if I can go back and forth every other week, or maybe I would have to set up two completely separate accounts, with the same product?

Is this crazy? Is this a thing? If so, how would one go about it?