You can use a dedicated domain for your cold emails, this way, you'll protect your main domain. If you go this way, here are some important things to pay attention to:
If you use a new domain with no emailing history, make sure to start slow and increase the volume as you gain trust and replies.
If you use GSuite, pay for at least 6 months of subscription ahead instead of paying monthly. Users of the monthly plan have reported that Google blocked their new domains pretty quickly.
Make sure to forward your dedicated domain (e.g. second-domain.com) to your main domain (yourcompany.com). This way, when someone tries to get to your website using your email address domain, they won't get to a dead end.
Reply to prospects who responded to your emails using your main domain. This way the transition to your real email is smooth.