emails are being rejected by google and blacklisted

I have a mail server that's currently sitting on the digital ocean platform.
The mail server is powered by Cyberpanel
Cyberpanel has 4 email domains on the server
mail.bourne.me
mail.megasave.net.au
mail.wwwmedia.world
mail.mediaemailreply.com

The problem is the an email address from the mail.wwwmedia.world domain was being used in our dating site (globallove.online) to send messages to our members (messages were daily updates, messages from other members, email verifications etc) which would be a minimum of 2000 emails a day going to mostly gmail addresses, and then of course what happened was google blacklisted our IP address and the mail was returned.

I contacted Digital ocean about this problem, and they responded to (the email is attached) who said that they are not an email host and some of their IP ranges are have a low reputation.

So the mail server needs to be moved to a good server, and use an email relay service like sendgrid.

I have setup a SendGrid account, and a new server to host the mail server (ovh.com)

So now I need this fixed, I have also setup mail.mediaemailreply.com to use this one only as the noreply email for all websites that I have.