Are you on iOS? If yes can you share the TestFlight link?

Instant mix is the circle icon with a slash through it, next to the play icon or play option.

If anyone needs Finamp TestFlight https://www.google.com/url?q=https://testflight.apple.com/join/UqHTQTSs&sa=U&sqi=2&ved=2ahUKEwjU0PuRhKOWAxVMNYYAHW2aDGAQFnoECA8QAQ&usg=AOvVaw0pVURvP7l3RV2frvZQ_MHx

Found it https://media1.tenor.com/m/XgU8qFqahwMAAAAd/not-for-you-mf-discord-only.gif