4 year old toddler

Hi parents . I gave birth to my 4 y/o when i was 15 . Thus , i didn’t give so much care and attention to him as i was still young . Whenever he needed entertainment and i was too tired from school & work , i’ll pass him my handphone/ tablet and let him play for hours until im awake . It affects alot of his developments , his diet as well . Now that i’m older , i want to do better and be there for him but his main interest is always on youtube , netflix etc. No matter how much i try , he will always prefer devices . He will throw tantrum and call me “ stupid “ whenever i dont resort to giving him the devices . Hitting me , biting me . Can someone tell me if i should bring him to the doctor ? Or will it gradually improve ? Also , his diet is terrible . He doesnt eat any solid other than rice n soup , & porridge . I see my friends’ children are all eating pasta , pizza etc and i’d really like that for him . Can someone tell me what i should do ? Must i bring him to a PD too ?