What you need to know is if you can reach at decent scale people that will pay enough to give you a fat margin of profit for your product.
So you need a product that does the job, you need a scalable distribution channel and you need customers to pay enough to give you 60%+ margins.
That’s it. There’s no way around it. With both physical and digital products you can let people pre order them.
You need distribution-product-price fit. When you achieve that you can pour gas on the fire.
TL;DR Just create a damn landing page connected to stripe and take pre orders and make sure the price gives you lots of margin. Then spam The distribution channel. That’s it.