WTB Open Port 25 Residental Proxies (Strictly for Email Validation / No Spam)

[Bugfoo]

Hey everyone,
I’m currently looking for a reliable proxy provider that allows outbound connections on port 25. I know asking for open port 25 usually sets off immediate alarm bells for spam, so I want to be completely transparent about my exact use case and traffic profile.
Why I need it: I am building a cold email SaaS, and I'm currently developing an email verification feature. The goal is to allow users to scrub their lists and avoid hard bounces or IP bans during bulk checks.
How it works (Technical Details): To verify the addresses accurately, my script performs a quick SMTP ping to remote mail servers.

1. It connects via port 25.
   
2. It sends the standard
   Code:

   EHLO
   ,
   
   Code:

   MAIL FROM
   , and
   
   Code:

   RCPT TO
   commands to check if the specific mailbox exists on the server.
   
3. As soon as the server responds to the
   Code:

   RCPT TO
   command, my script intentionally interrupts and drops the connection.
   

My Guarantee:

• No Payload: I am absolutely not transmitting any actual email data or
  
  Code:

  DATA
  commands.
  
• No Spam: Zero emails are being sent through these proxies. It is strictly for validation/pinging.
  

I’ve been DMing providers individually, but I figured I would cast a wider net here to see if anyone can accommodate this. If you run a proxy service that can unblock port 25 for this specific validation use case—or if you can point me toward a provider who does—please let me know below or shoot me a DM.
I am more than happy to do a trial run so you can monitor the traffic and verify that it's just SMTP pings.
Thanks in advance!