heya did u post a picture of your previous mallsai
because theres always a chance to grow it into a tree dude...
its just that you may have to plant it into a large pot or even the garden, to get it growing in size and thickness...it can u know but once its settled in a bonsai pot...they pretty much seize to grow.
but unless ur bored of that tree and want something else, something more grown up and settled to admire and care for.......rather than watchin something grow that you have doubts for.
but still.....keep your first bonsai tree...when you gain more experience...you may in the near future want to experiement with it and maybe try to make it grow.
ficus can cope indoors but they will grow slower compared to the ones outdoor...
you may aswell get it outdoors....they cope well in the heat too.