what is different between gping to and going to be

i am going to temple. में मंदिर को जा रहा हूं।( "going" as a main verb) I am going to do exercise. मैं एक्सरसाइज करने वाला हूं।( "going" as a supporting verb) i am going to play cricket. मैं क्रिकेट खेलने जाने वाला हूं। I am going to be a doctor after 5 year MBBS course. 5 साल के MBBS कोर्स के बाद मैं डाक‌्टर बनने वाला हूं। (be as a main verb, and " going to" as a supporting verb) "going to" means" वाला

be menz to be something nd only going to is a verb

आज बदलो वाला दिन होने वाला है | it is going to be a cloudy day today. शाम को बारिश होने वाली है | it is going to rain in the evning. is dono sentence me bat ek hi ho rhi h but fir bhi going to and going to be me difference kyu h?