Genius has an integration on their lyrics pages with Apple Music, and this extension simply replaces that with a Spotify miniplayer. It is not perfect, but it is reasonably accurate. Unfortunately, this has to use the normal Spotify search API since I don't have an Apple developer account (and this uses different keys for each user anyway).
Here are the links to install it:
Here is a picture of a Genius page with the extension enabled:
And without:
Log in and create a new Spotify application here. You can use any name and description, and this will not cost you any extra money.
Then, paste the client ID and secret key into the proper fields in the extension popup and save. You will know it has worked when you can close and reopen the popup, and the text boxes are automatically filled with the correct values.
Then, you can use Genius as normal! Except with a working miniplayer instead of low-quality, thirty-second previews.