I need assistance to ensure correct vps configuration with Cloudflare

Good night, I have a debian plesk apache vps, is it possible anyway to put the reverse dns of the email with proxy?
I intend to completely obfuscate the ip of the server, if necessary acquire a remote mail server to send another ip in the headers.
The aim is to block attacks on the vps, a way to separate the domain and the ip of the server, so as not to allow the information of the server and connections to all clients that browse the domain.
Can you help in the best way to resolve the situation?

I need to resolve the errors in dns configuration:
Reverse DNS does not match SMTP Banner
SOA Expire Value is out of recommended range
SOA Serial Number Format is Invalid
And others…

Information I found:

Best regards, RS.

If you host email on the same server as your website, you’ll never be able to obfuscate the IP address of the server unless you’re on the very expensive Enterprise plan here.

Do you know the best way to send emails through a domain ipfailover or remotely in a secure way?
I have the vps with Plesk where you have the files, an ip is added to register these domains in the account.
The domain has a different ip from the vps, and it will be through this ip or another that sends the emails, but it will always be sent by the vps.
The domain always sends the email with the origin registration, ip of the domain and not of the server.
This domain can show the ip, and visitors can only open port 443, all others are turned off.
So the server ip is hidden, but in Reverse dns it is never correct.
I just need to stay safe and avoid attacks with access attempts, and others.
I don’t understand anything about dns and security between server and vps, and I need help for this service to be safe and to be informed of the best solution.
If anyone can help, inform or develop, I would appreciate it.
Best regards, RS.