Hi, I’m not sure where you can find some templates but I know for sure is that the templates that come with Unreal Engine are good enough to get you started if you can’t buy content from the marketplace, I couldn’t pay for marketplace items due to my location but I did purchase 1 pack, Explosion Builder because it looked better than anything I could make myself, I had to buy it directly from the creator, everything else for my game I either created myself or used the free assets from epic, all you have to do is find good enough tutorials and software then learn what you need to learn, there is a lot free ones out there. And if you don’t have a team and don’t plan on having 1 I also recommend learn how to model and animate, within 2 years I was able to learn, create, and launch my own game on steam, but I already knew how to model and animate so that was a big advantage for me in terms of content creation.
In the end I can say you don’t need marketplace to make a good game, market place makes it a bit easier and faster. What you really need is to learn the right skills and knowledge, without the right skills and knowledge marketplace items will be useless to you. tutorials are your best friend, just dig in and don’t give up.