Warming up email/ip's is that really a thing?

I am going to be acquiring a bunch of proxies, assuming they are not blacklisted, I will associate each one with an email address I create and then send emails accordingly, however, do I need to do something to "warm up" the ip or email meaning so I do not come off as a spammer. I only plan to send 100 emails a day from each email account.

I heard that you should warm them up but I'm not sure. For a project I got a new email address and warmed it up for a week. Just sent emails from it and signed up for some mailing lists so it looks legit. I did that for about a week and then started cold emailing. Never had a problem. But I'm only sending like 5 emails a day.

Yes domain and ip warmup is a thing and it's important.