Have you been to the GP and asked for any tests?
There are several conditions that can cause slow metabolism and affect weight. You have a food diary you can show them to evidence that reduced food intake isn't working.
I'd ask for a HBAC1 to test for diabetes, a thyroid panel, a hormone panel to test for signs of menopause and standard vitamin/mineral levels to look for deficiencies.
It could well be that you have an under active thyroid or are prediabetic, if either of those were the case then you may need a different medication instead of Ozempic, or a different dosage.