Use this link to download the win-capture-audio plugin for OBS: https://github.com/bozbez/win-capture-audio/releases/

Here is a nice video tutorial on how to set it up and use it:

This method is super easy and can be used with any window you are trying to capture audio from! I know that PvZ is typically a weird one to capture audio for, but I have already tested it and it captures both the sound effects and music. Shoutout to the RRLAT community for telling me about this in the first place.