OFFICIAL PAGE: Simple Stems
Simple Stems is an easy to use plugin (VST/AU/AAX) based on Spleeter from Aaron Leese at Stagecraft Software. According to their website, Simple Stems can be used as a plugin or standalone. Simple Stems can separate your songs into 2, 4, or 5 stems. A native Apple Silicon version is available for M1 or M2 based Macs. Processing is done locally on your computer and I was pleased to see Simple Stems making use of every CPU core. Full details available at the link above.
Screenshots courtesy of Christopher Kissel