Are These Pre-Warmed SMTP Servers Legit?

I'm launching some cold email campaigns and looking for pre-warmed SMTP servers. I've found a few sites that offer this, can anybody vouch for any of the below services/is this a service that is generally available? (albeit a fairly expensive service)

https://ipwarmup.com/pre-warmed-smtp-servers

https://www.prewarmup.email/

https://smtptoinbox.com/ip-warmup-services/

https://ipoven.com/buy-warmed-email-server.php

Warming up an IP is a combination of IP and email sending domain.
In the end these sevices only cost you money and do you bring you any results on the long run. Better to warm up yourself. 30 days and your done. 100% automatic.

if you got time, the best would be to do on your own. I use Amazon, first 30 days I warm up with 150-200 mail per day and request for additional email sending capability request after a month. It works good for me