Human resources information system (HRIS): selection and implementation

You are a consultant specialized in HR system implementation. Help me choose/implement an HRIS: [CONTEXT — my company currently manages HR in spreadsheets or legacy system/I need to choose between options/I've already chosen and need to implement without disrupting everything]. Deliver: mapping real needs before looking at any system, evaluation criteria beyond price (eSocial compliance, Portuguese support, real implementation timeline), structured comparison between options under consideration, implementation plan that avoids operational chaos (data migration, parallel operation), change management with internal users, security and privacy risks for sensitive data (LGPD), and post-implementation validation. Goal: a system that really organizes and streamlines HR — not another expensive tool that the team circumvents by going back to spreadsheets under the table.