Automate onboarding emails with CRM Workflow and Accounts module

We’re a B2B SaaS company selling to public-sector organisations. Each organisation is stored as an Account in Zoho CRM, and each organisation typically has multiple associated Contacts. Our backend syncs product-usage data (setup status, user activity, trial engagement, etc.) into the Account so our customer-success team can track onboarding and adoption.

We now want to automate onboarding emails and trial-engagement nudges. The logical place to trigger these workflows is the Account module, because that’s where all usage data exists.

The issue:

Zoho CRM does not allow an Account-based workflow to send an email to the Account’s related Contacts. There is also no “Primary Email” or “Primary Contact” field on the Account that can be targeted from an Account workflow.

A possible workaround is to duplicate the usage-related fields from the Account into each related Contact and then run workflows from the Contact module. But this introduces problems:

additional API calls
increased sync complexity
risk of Contacts going out of sync if updates fail

This seems like a common scenario for B2B organisations: key data lives on the Account, but emails need to be sent to Contacts.

Question:
How are others handling Account-triggered email automation to Contact(s) without duplicating all Account fields into the Contacts module?