Workplace democracy isn’t necessarily a core concept of Socialism, at least not in the Marxian sense. Removing the issues that come with the profit motive alleviates issues you describe. Instead, Marxists advocate for public ownership and central planning with extensive democratic controls, without necessitating competing democratic worker coops. Engels argued against such a concept in Anti-Dühring, actually, believing such a system to revert to Capitalism through competition and accumulation.