I’ll give you the no BS answer as I have 40 years in the Architecture field.
If you want to move past the lower ranks $500.00 to $1000.00 per still image you will need to be able to compete with Architects, designers, photographers and exceptional talent. Having a good knowledge of Architecture, Interior Architecture, good design, photography will help you immensely. Every Architecture student coming out of school knows 3D now, the competition is fierce especially from the 3rd world where prices are rock bottom. Can you get 4K for a rendering, sure IF you are at the level of the best in the field.
If it’s something you are passionate about then go for it just don’t expect a lot of money. An Architecture firm can get an Architect that has great 3D skills for under 50K a year.