The key is going to make a stunning portfolio first. You do not need 38 projects to gain attention. Look at Koola, he only did a couple projects that showed the world how Unreal Engine can look good. Have a very professional looking website, with great demo projects and I’m sure you’ll get clients. You can work with anyone in the world, that’s the cool thing. As you said, it can be architecture, it can be industrial design (my paid job was for a Marina visualisation), it can be urban planning. Even if you don’t sell many playable projects or virtual reality projects (because the client require a good pc/ VR device but with the cloud possibilities it’s going to change anyway) you can always sell movies. Rendering a movie with a traditionnal renderer takes a huge amount of time and is costly. Rendering a movie with Unreal is instant and cost nothing! That’s a huge advantage in my opinion. A well made movie is always cooler than the best of the picture I think.
If you also want to learn an offline Rendering software I strongly suggest you to have a look at Corona Renderer. They offer a 45 days unlimited demo, and after that they offer monthly payment subscription for about 25$. It’s a very well made renderer, alot easier to learn than VRAY and can produce stunning results (have a look at the gallery in their forums). Instead of paying a 1000$ license to Vray and struggle with their 34 000 settings. With Corona you can do all kind of 3d viz jobs. With Unreal you can do even cooler stuff tho 