What are the most effective exercises for reducing belly fat and a stronger core?

I have started my weightloss journey about a month ago for the Nth number of time. But this time i am all in, knowing that it has to be a lifestyle change and not another draconian diet. I started at 208lbs. I am doing 15/9 intermittent fasting. I try to hit my macros everyday. I workout 5 days a week. I take help from the Internet and create my own workout plan for each day. I feel like i am not doing enough or right exercises to train my core and in extension losing belly fat. Also, i am a vegetarian, so i am not able to hit my protein requirement consistently everyday. It is okay if i meet 65-70% of it?