Are you using the plugin Roll-up reporting?
Have you noticed if Matomo get slower and sometimes crash?
We created a roll-up to include all of our websites.We have then experienced that sometimes it takes a lot longer to load the reports, and sometimes we get en error-message and need to retry or refresh the page/report.
Our installation of Matomo is large and we have high traffic. So perhaps some caution is needed when it comes to creating roll ups for large installations with many websites and high traffic.
All the best regards,