[blisseyGo]

You might find this useful:

https://www.linuxbabe.com/mail-server/ip-blacklist-removal

Especially the part about "Rule of Thumb for Running Mail Server on a New IP Address

When you run a mail server on a new IP address, you should not use this IP address to send newsletters (aka marketing emails) right away. Instead, you should use this IP address to send transactional emails for a period of time to improve the reputation.

You may also want to use SMTP relay to send emails for a few days because SMTP relay services have a high IP reputation. After that, send emails directly to the familiar recipients."