Fix Google Workspace Email Deliverability

We are seeking an expert to resolve email deliverability issues with our Google Workspace account. The task involves setting up SPF, DKIM, DMARC, and DNS records to ensure emails are delivered successfully. The ideal candidate will have experience in email deliverability and DNS management. This is a part-time project expected to be completed in less than a month. CONTEXT: We are a small AI consulting company using Google Workspace (Gmail) with our own domain. We are experiencing email delivery issues when sending emails to some companies. Most emails work normally, but certain domains reject our emails. Example errors include: - 550 5.7.1 Message Rejected due to Sending Domain Owners SPF Policy - 209.85.xxx.xxx is not allowed to send mail from our domain This affects all users in our organization (currently 4 Google Workspace accounts), so this is clearly a domain configuration issue rather than an individual account problem. We need an experienced Google Workspace / DNS / Email Deliverability expert to diagnose and permanently fix the issue.