The best open source alternative to Matomo is Plausible Analytics. If that doesn't suit you, our users have ranked more than 100 alternatives to Matomo and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Matomo are GoAccess (Free, Open Source), Counter (Free, Open Source), Open Web Analytics (Free, Open Source) and umami (Free, Open Source).
Do you need a simple tool to know your website statistics? Do you need to represent these statistics? Are you caring about your users’ privacy while analyzing who are interested in your business or website?