I need advice for my toddler

My son is 20 months old. He was always advanced and on track with everything except for his speech. He is still not talking and doesn’t wave, point, or even say hi, bye, cat or dog. I do use the tv to entertain him when doing chores around the house or cooking so I can get those done without a million interruptions, it’s not good I know. I saw a speech therapist today who told me no more tv which I understood why. I’ve tried books he just likes to flip through the pages and won’t look at the pictures or even let me finish reading the first sentence without him tossing the book or moving on to the next thing. I’m talking to him as much as I can but he doesn’t look at me he keeps his head down and plays with his blocks it’s not getting through to him. I’m worried maybe I’m not doing enough or there’s more I should be doing? With covid going on I can’t take him to any speech classes in person it’s all over virtual video and that’s not really helping him since he doesn’t have the attention span to sit through a video chat. He’s spent most of his life in quarantine unfortunately. Any advice is appreciated on how I can encourage him to start speaking.