Can you use stock photos without getting delisted? But, of course! As long as you don't steal them.

If you WANT to go low effort, there are model and texture packs sold en masse, music, pictures, graphics engines, … you get all those off the shelf. Heck, you don't even have to design the levels yourself, if you don't want to. You can push out an app per day, if that's what you want.

Most phone apps are no more complicated than any other piece of JavaScript or website.

Having access to all these resources is a double-edged sword. You absolutely can leverage that to create even higher quality software, or enable people to build great games, that would otherwise not have been able to, since they lack a particular skill (like making music, or drawing textures). But you may also abuse the options you got to make an entire profession look bad by flooding the market with low effort apps that drown out the competition by sheer mass.

I mean, I prefer a more cerebral puzzler myself -- seriously GoG, Baba is You , make it happen
but, damn, some of these posts seem personal.

Who hurt you?