First, I think it’s important to know which accent you want choose for your English. And as per reference, watching movies or dramas would be a good choice. As they sound more natural than copying the pronunciation of any robots.

Because English spelling is notoriously inconsistent, it can be helpful to listen to the words spoken aloud in a video clip from a movie or television show. Then copy the person speaking and make yourself sound like them. When you learn from movie or television show dialogue, you will hear some regional accents even within American content, so choose an actor whose accent you want to imitate.

I think imitation is a good way to practice pronunciations. Nowadays there are a lot of dictionary apps available, which you can choose according to your preferred accent.

are your methods I strongly suggest you get feedback. It's much harder to unlearn something wrong, than to learn it correctly the first time.

For practicing I practice it with songs, for example catch one that you love and you'll submerge in the lyrics and its pronunciation.