There are lots of online tools available that can help you to change your YouTube to WAV. These tools are: 

OnlineVideoConverter: Visit the OnlineVideoConverter website, paste the YouTube video URL, select the output format as WAV, click on “Start” to begin the conversion, and download the converted WAV file.

4K Video Downloader: Download and install 4K Video Downloader, copy the YouTube video URL, open 4K Video Downloader and click on “Paste Link”, choose the video quality and format (WAV), and then click “Download” to start the process.Y2Mate (Browser Extension): Install the Y2Mate extension on your browser, and go to the YouTube video you want to convert. Click the Y2Mate icon to download the video and choose the WAV format for conversion.