Question 2 PTR for 2 IPs but only 1 host

[Pedro1]

Hello.

First of all, sorry if I say something that is not correct.
I have 1 VPS with Plesk. Name host.domain.com
This server has 2 IP4

The main IP (IP1) has a DNS type A zone host name: host.domain.com

Secondary IP (IP2) is assigned to a domain from a client. For example: domaincliente.com and have a DNS zone type with the domain name.

PTR (IP1) is set to host.domain.com for rDNS
PTR (IP2) is set to dominiocliente.com for rDNS

My problem is sending emails.
All emails contained the name of the host in header. HELO. host.domain.com
With the IP1 everything it is correct and no problem.
With the IP2 the problem is that the rDNS tells me that is not correct, because the emails are sent from host.domain.com but rDNS IP2 is dominiocliente.com indicates that it is and should be the same.

QUESTION.
I can put the two PTR establish the same hots.domain.com? Is this correct?
Or how I should configure Plesk to set IP1 for shared ip to other domains and IP2 only for one domain.?
Should I use robin DNS via Cloudflare for example?

Thnaks a lot.