To change MP3 bitrate, it is suggested that you do it using the desktop tool or online tool. I have ever tried it on my Huawei P30. It can't practice well. So I change to use a desktop video editor called Joyoshare Media Cutter to help me. Due to its previous promotion, I choose it. Indeed, it is a professional video editing program as advertised. It comes with two modes, not only allowing me to customize codec, bit rate, channel, sample rate, resolution, frame rate, aspect ratio, etc. but also supporting lossless cutting, splitting, merging, converting, cropping, rotating, watermarking, subtitling, and etc. Besides it, there are many other tools to get the thing done, like MP3 Quality Modifier, Online Audio Converter, etc. You can choose the proper one to work with.