I have hit a plateau on my cut even though I was on a 500kcal deficit.

I've been experimenting with replacing all my carbs with vegetables. I drink coffee before my workouts to get the energy needed. I still eat more than enough proteins compared to my macro goal, mainly chicken breasts. I use very little, to no fat at all, mostly in the forms of peanuts.

This resulted in me being on a near 1000kcal deficit. I still feel fine. Im not hungry because vegetables is very filling. And I have enough energy for my daily life and the weight started decreasing again.

My question is: would this be bad in the long term? I know being on a huge deficit would likely make me lose muscles, but if I still take in enough proteins, would that help preserve muscles, all things considered?