Mac storage basics · Caches, logs and temporary files
How do I stop Spotify or other streaming apps using so much space?
Short answer: Use the app's own Storage settings: clear its cache, and turn off downloads you no longer need offline. Some apps let you choose another location for offline files.
Streaming apps keep two kinds of data: a cache of recently played content and downloads you saved for offline listening. In Spotify, the Storage section of its settings shows both and has a button to clear the cache; removing downloads is done by turning off download on the playlists or albums.
Some apps let you move their offline storage to another location from the same settings screen, which is the cleanest way to put it on an external drive.
Chat, music and meeting apps are among the usual suspects Storage Studio's What's Using Space checks by name.