it does not look lazy. if it was just a flip then it would look lazy. it takes constant math in my head to draw these images.
Even so, it results in a perfectly symmetrical image, which looks unnatural and lazy.
And even if the ref is your own, you should mention that you're using ref. Moreover, for your images of celebrities, I doubt the ref is your own.
this is from my own reference. it is a picture of my aunt that i took during a christmas party. it is not a mirror image. it is symmetrical but it is drawn that way by averaging each side of the face into a non existant image. viewers often think that i just flip some half of the face but what i do is not that simple or else it would be highly noticeable.
I think aside from more careful/controlled colour choices, your work would benefit heavily from not being mirrored. Pixel that other half instead of just mirroring the first half! Humans are never perfectly symmetrical, so perfect symmetry looks unnatural and sends your portraits deep into the uncanny valley.
Also, you should credit the references you use. If possible, link to them, if that's not possible, then at least mention what the reference was and where/who it came from.
i use celebrity references from google.