I don’t know where you got your definition of capitalism “results in economic singularities and infinite wealth for everyone”, but it’s wrong. The West is currently in late-stage capitalism, which is always the outcome of a capitalist system: wealth and power gets consolidated into the hands of the few, while the many suffer.

The term “leftist” can best be described politically, as supporting the political left. The problem with that term currently is that it’s used to define non-political ideology as well, like social aspects such as empathy/sympathy. I’m unsure where you stand when you call yourself “leftist” so it’s hard to say if your definition can mix with capitalism.

Fundamentally, in my opinion no, enjoying capitalsim is supporting a system that inherently causes inequality, wealth gaps, and the concept of profits over people, which are the opposite of a standard definition of “leftist” beliefs no matter how you define it.

My question to you is, would you still blindly support capitalism if you were one of the many who didn’t benefit from it?