Indie programmers have no advantage on popular commercial engines. These engines simplify a lot of programming work, the focus of the competition will be on large-scale advanced art, this is the advantage of capital, indie programmers are at a natural disadvantage.
Popular engine can cause serious homogeneity. the same engine is used by countless people, no matter how innovative you are, the probability of meeting similar people is very high. Especially some popular plug-ins or good function, will causes a lot of products to be very similar.
I learned about the game industry late, but when I saw some game video, I was shocked, how come so many games are so similar! Designing my own engine maybe avoid similarities with others. Games are creative products, it's very important not to repeat with others.
Some game's background is oily or blurred , I don't like, I like sharp background. Although I don't know much about these engines, but I guess it's not because of engine but because of distance, the content of the art scene is proportional to the square of the distance. Because the distance and the space are big, to have a clear background, it need a lot of art scenes and takes a huge amount of art work, obviously such a work mode is not suitable for a solo programmer. By my intuition, design an own engine, short range and local use 3D, distant background use 2D, the game making workload may be low, this mode suits me.
Review after game finished, my intuition is correct, the art workload of a game is too great for a solo programmer.