We are on the free plan so we have set up a new Vendor workspace and invite all our collaborators there.

I'm sorry to say this but I felt like Zoho products are kind of sub-standard compared to commercial tools like Salesforce, Dynamic CRM, or open source solutions like Odoo. Tried Zoho email, books…

Did you consider Odoo? They offer both cloud & hosted community edition. You may need some tech support if you want to host it yourself.

You may consider Redmine CRM plugin…