There’s no real way to keep using Gmail and get business communications, especially automations and batch emails, delivered to the inbox. There’s also absolutely nothing you can do about this when it comes to free @gmail.com addresses, since you don’t control their email server.
I would recommend signing up for your own paid business email (Google Workspace), properly configuring the email server, and then slowly ramping up your sending volume gradually while monitoring feedback loops, Postmaster data, DMARC reports, and other key indicators.
