Scalable Workarounds for HubSpot and Salesforce Activity Sync Issues

[HubSpot question] We're in the middle of Hubspot implementation and have faced a major hurdle in Hubspot<>Salesforce with Activity sync. Our BDR and Sales teams use Hubspot for TOFU activities and Salesforce for Opportunity management, whereas our CSMs only use Salesforce. It's vital that any activities generated in Hubspot are pushed into Salesforce with relevant associations (to User, Account, Contact records). It seems that native Hubspot integration doesn't really support this. Has anyone found scalable workarounds to this?