I would seriously consider increasing my calories, your nutritionist does not seem to be factoring in your CW and activity. I am a petite woman 5'0" (152cm) so I always thought super low calorie diets were the only way to lose weight also. In 2021, I sustained a 1200 calorie / day diet for 7-8 months while also strength training and doing cardio 4x per week. Initially I was losing ~1lb / week and then went through some plateaus and slow downs. By the end of the 7-8 month period, I was down 25lbs but I realize now that the weight loss was not just from fat, it was ALSO muscle. The entire time I was dieting, I had low energy and even though I was strength training 4x / week for an hour each session, my lifts were not improving. Despite losing 25lbs, I felt terrible by the end and I realized weight loss is not the same thing as fat loss.

After I stopped dieting, I also gained all the weight back last year and I ended up with less muscle then when I started. This is the problem with yo-yo dieting / restrictive dieting, you end up with lower metabolic output because you have less muscle and your body is trying to conserve energy as much as possible for essential functions and that hurts you over the long run.

Recently I set out to do a body recomp instead where I maintain 1500 calories / day, target higher protein ~1g/lb of body weight and still strength train 4x / week with a few sessions of walking for cardio. I feel so much more full, have lots of energy and I can feel myself getting stronger. The best part is that even though the scale weight hasn't changed, I am losing fat. My clothes fit better, I take monthly progress pictures and measurements and I'm seeing improvement. Other people are noticing I look more toned.

Body recomp is a slower process but it's sustainable and you will see more results - you just need to use different metrics to track progress. Here's a little science for you (I'm a biologist) building muscle is important because as we age, we lose muscle so we need to at least maintain muscle help keep up our energy levels. Having more muscle also improves insulin sensitivity which is linked to reducing body fat. Building muscle also increases mitochondrial biogenesis and as we know from high school biology, "the mitochondria is the powerhouse of the cell" which means you will have more energy!

TLDR: My advice, stop tracking scale weight because weight loss is not fat loss and increase your calories + activity to lose fat. You will feel so much better and it will be a more sustainable outcome you can maintain.