Same roots, separate paths
Both products come out of the Piwik project and then developed in different directions. Matomo stayed open source and lives from its community and plugin ecosystem. Piwik PRO rebuilt the suite for enterprise procurement: contract, SLA, compliance features.
For the tool decision that means you are comparing two operating and responsibility models more than two analytics products. The criteria table above shows the editorial scores; the per-tool breakdowns live on the tool pages.
Both tools in the wider field, with GA4, Plausible CE and etracker: GDPR-compliant analytics.