Maybe you can also try Joyoshare VidiKit. It’s my favorite, and I think it’s easier to use than most other screen recorders. It can record screen in 4K or HD quality. No watermark, no time limit, and no latency, which totally amazes me.
Would a screen recorder be able to help you? There are many free and paid ones you can choose from. You can use them to record what you need and save it as a video or audio file. I myself usually use a screen recorder called Joyoshare VidiKit https://www.joyoshare.com/vidikit/. It supports many output formats and built-in editing tools. Maybe it can help you. Just to add, you can get a free license of this tool or an Amazon gift card by commenting one of its Facebook post: https://www.facebook.com/JoyoshareGlobal/posts/4097852883607319
Sometimes I would also use Joyoshare VidiKit to cut videos losslessly. It supports entering start/end time of a video into the temporal interval with millisecond precision. It is much more easy-to-use I think.
Try 2Conv. It is my favorite. Free and online, simple yet very capable. It is able to save YouTube videos in MP3, MP4 and AVI. You could also use Joyoshare Screen Recorder as an alternative if you would like to save any length of a song or download music files from other online sites.