Magento 2.4.8-p1: Emails not delivered to Gmail/Outlook but working for Mailinator/TempMail

I am facing an email deliverability issue in Magento 2.4.8-p1.

Transactional emails (e.g., customer registration, order emails) are:

✅ Successfully received on Mailinator / temporary email services

❌ Not received on Gmail and Outlook accounts

Environment –

Magento Version: 2.4.8-p1

Environment: Staging server

Local setup (DDEV): Working fine for all email providers