You need to decide what it is you want to do first. Trying to create a comic, and a movie and build models to sell are all different projects that each take considerable amounts of time investment. Doing it all by yourself at the same time is virtually impossible and will make it harder to get anything done at all. And I say that from experience.

If you don't have a story then you might look into freelancing for other comic book writers who need artists and are willing to pay for your work. That would probably be the fastest route to a paycheck in the world of indie comics. But that also requires having a good art portfolio to show them. It doesn't necessarily have to be comic work but it needs to demonstrate the best of your abilities.

I've been working on my own comic for the last 12+ years, which is based on a story I've been writing since 1990ish. I've had similar ideas, that I would build the models I need to use in the comic and sell the models which would also help to promote the comic. That alone has sucked up so much time that I still haven't gotten to the actual creation of the comic yet. I have roughed out story boards scattered between sketch books and psd files, a ton of reference material, literally thousands of pages of notes, character sketches, etc., that I've amassed over the years, but I'm still a long way off from turning any of it into a polished comic book ready for an audience. I just work on it a little at a time when I can. At one point a few years back I was even working with a few other people on adapting it into an rpg. We had started putting together a kickstarter campaign for it but it all got to be too much and I wasn't getting any real progress made, so I went back to the basics of just working on formulating all of it into a tangible story.

What I've found from my own research (and listening to what other comic artists who have published their own work have to say on it) is that most digital-only comics don't have the same appeal that print comics have, and for the most part the return on them in terms of individual sales between print vs digital is pretty much the same, so you're not really saving anything by going purely digital. With comic books people prefer having the physical copy in hand. They might read a digital one but getting them to buy it is a lot harder than it is to get them to buy a physical copy, even when the digital is cheaper. Digital eliminates the trade aspect of the comic book industry, which has pretty much always been the life blood of the industry. Most people sell or trade their comics when they're done with them and only collect their favorites. That's pretty much what keeps comic book shops in business. If you spend much time in comic shops you'll notice that their used section is always a hundred times bigger than their new, and they almost always sell other stuff like vintage toys and collectables. The trade value of all that is eliminated in digital comics. That doesn't mean that there are no digital comics out there that are making good money, it's just that it's not the route most comic artists take because return on investment tends to be a lot lower. It costs the same to develop a digital comic as it does a print comic. The only difference is the cost of producing the print version, but those costs are still taken up by distributing the digital version. Even if they start out with a purely digital version - which a lot of them do - they still work print into their design plan at some point. Plus, its easier to promote your comic at comic shows and various events if you can hand someone a physical copy to look through instead of scrolling through some pdf pages on your ipad. IMO, comic book enthusiasts are art collectors in their own way so they want to have that physical copy to interact with. However, it almost seems to be the reverse on the adult oriented side of comic books, where digital and even 3D generated seem to be becoming the norm. There's still a lot of printed adult comics out there but its harder to get them marketed in print format it seems, whereas there are a ton of websites that publish digital adult comics and a lot of them are always looking for new artists.

The short of it is, none of it is an easy task and it's probably not going to make you rich any time soon. That's why the whole reason behind getting into it has to be because you want to make comics, not because you want to get rich. If you're good at making comics then the money will come later. Here's a video from a guy whose own comic won best indie comic in the UK back in 2014. Even with that he had to move back in with his parents because it cost him more to produce it than he made in sales.