Teaching pronunciation is a speciality. Most teachers are trained to teach grammar and vocabulary. Very few are trained to teach pronunciation. italki has about 3000 English teachers. About 700 teachers offer pronunciation practice in their teacher profile. About ten mention specialized training in phonetics and phonology. Phil and I are two of those ten. Use "Find a Teacher" on the website and enter "phonology" as a skill. Then contact a few teachers.

There's a woman with a video who explains 50 English phrases in 10 minutes. Her intonation and rhythm are very good, suggest you listen closely and repeat. These phrases almost have to be said with the proper rhythm or you won't be understood. https://youtu.be/bj5btO2nvt8 And of course if you can find someone to practice English with regularly that would help a lot.

你好，Kai, I’ve read your post and I understand where you’re coming from — there are lots of good reasons for wanting to acquire a near-native accent, and rhythm and intonation certainly are key elements. It’s all about "acquiring" a new accent — not "reducing" your native accent — you need your native accent for when you speak your native language :) Your idea to listen and repeat is good, at the same time, a solid understanding of phonology (including prosody) will allow you to enjoy much better progress, as will an understanding of how to use the articulatory organs the way native speakers do. I never advertise in the fora, but since you've asked, if you’re serious, you are invited to check out my teacher profile, watch my video, and shoot me a message. You can read my course description* to learn how I can provide you with massive support for American accent acquisition. When you book a class with me, we won’t get the job finished overnight, but you will immediately understand how I get results, and you’ll experience significant progress with every single lesson. You’ll also get coaching and feedback for your independent practice. Talk to you later, Phil *Course title: American Accent Mastery — Near native speaking and LISTENING skills — see description!

I just got a book on English pronunciation, it comes with a DVD and is called something like "Accent Reduction".