Comparison
FabFilter Pro-Q 4 vs TDR Nova: is the paid EQ worth it?
Should I buy FabFilter Pro-Q 4 or use the free TDR Nova?
Start with TDR Nova. It is free, and its documentation covers the core of dynamic EQ: four bands with their own threshold, ratio, attack and release, high- and low-pass filters, a wideband dynamics section, external side-chain input and mid or side processing. It runs on Linux as well as macOS and Windows.