I was like that too ngl. Tbvh, I had same weight as you. I did exercises daily but didn't gained my weight. A good guy from gym suggested me to take creatine for some time and once you achieve the target weight, you should slowly stop consuming it. I took 2kg in 2 months I guess(not accurately sure) and I gained my weight from 45kg to 57kg. I stopped taking it and my weight got lil bit low like rn it's 52kg or 53. Also drink a lot of water if you take creatine and I prefer taking it with raw milk(unpasteurized).
PS: Eat a lot of food(majorly healthy).