Viewing Microsoft Project (mpp) files in SharePoint Online?

In SharePoint Server 2016, we had Project Server integration, so we could publish Project 'mpp' files to our SharePoint environment which the project team could view the alerts. We migrated our SP sites to SharePoint Online, and decom'd SPS 2016. We only have M365 E3 so are wondering what options we have for publishing Project documents in SPO. Is there anything we can leverage in terms of web parts or free viewers? or will we have to license Project Server Online (whatever its called these days) for people without Microsoft Project licenses to view the Project Plan documents (mpp files).