Who each platform is really for
Odoo
Odoo is a broad open-source business suite with a wide module catalogue and a large global partner network. That breadth suits businesses that want one system covering many departments and expect to work with an implementation partner. The scale of the ecosystem means more available apps, more consultants and more people who have solved a problem similar to yours before.
ERPNext
ERPNext is an open-source ERP built on the Frappe framework, developed by a company based in India, with an active community and strong local statutory coverage including Indian tax requirements. That suits businesses that value a coherent single codebase, want to customise on a consistent framework, and appreciate localisation that reflects how Indian compliance actually works.
Both platforms evolve quickly, so confirm current module coverage and licensing for the version you intend to deploy.