Updating to Audacity 3.0.2 may be a problem (unless your granddaughter can build from source), however, just updating to Mint 20.1 should automatically give you a more recent version of Audacity (2.3.3 I think), which is recent enough for macros.
Updating to Audacity 3.0.2 may be a problem (unless your granddaughter can build from source), however, just updating to Mint 20.1 should automatically give you a more recent version of Audacity (2.3.3 I think), which is recent enough for macros.