Then, you can only solve the problem by knowing the three voices of high school and low school. I'm afraid I can only give an example. I am a male voice, and I know more about male voices. Let's take male voices as an example. 1. Tenor singers, first of all, can generally have good A2 and C3 in popular singing. For example, Tom Chang g3, Zhang Yu f3, e3, Xin d3, Sun Nan c3, ... 2. There are relatively many mezzo-soprano singers. In popular singing, the real tenor can only reach G2 and A2. Such as Jacky Cheung, Andy Lau, Wilber Pan, Xiaogang and Wang Leehom. Chen Chusheng ... Bass singers (traditionally, D2 and E2 have the highest pitch, which is very rare in pop music. I didn't notice them. It should be said that there are no bass singers in popular singing. Well, the example is over. After the above example, you should be able to analyze what kind of sound belongs to high pitch and what kind of sound belongs to midrange.
Now let's solve the problem. 1, please ask yourself, can't you sing the songs of those singers above? If you can't sing a high-pitched singer's song, it proves normal. You should be a tenor. If you want to be a tenor, it is not absolutely impossible. There are ways to do it. This method was summed up by myself. I went from a standard tenor to a good tenor. Now there is a very solid c3, and the highest C3 can reach d3 (instantly), so what I want to prove is that it is impossible in traditional teaching. Please make sure that the alto may become higher. The method is to stabilize the midrange first, and then imitate the feeling of high-pitched singers singing and move up step by step. It takes time, so we can't worry. If you can't sing the songs of the mezzo-soprano singer mentioned above, it proves that there are two problems. One is that you have a serious voice problem, and the other is that you are a standard bass singer. I think the latter is very unlikely, because there are really few popular bass among men, and most people can sing F2. If you belong to the first situation of the second question, you must find a vocal music teacher to help you open your voice and correct your voice.
Regarding the sense of rhythm of music (that is, the beat problem you mentioned), one of the easiest ways is to listen more and listen carefully and analyze where each song begins. You need to practice more and keep your rhythm steady, such as buying a metronome (which is sold in a musical instrument store). I don't think this method will have much effect on you. Now that you know and find your own problems, it proves that your natural rhythm doesn't feel very good. Then there is the best and most effective method. It is to practice listening and ears, and it is best to learn a musical instrument. Maybe you won't understand what I told you, but there is no other way. Then I finally suggest you learn music. Learn musical instruments and vocal music.
If you think my answer is very detailed, please give some points, haha.