Cold outreach: do you send from your main domain or a separate one?

Quick one for anyone doing outreach.

I've spent a lot of years around CRMs and email setups, and this comes up every single time someone starts cold emailing. Send from your main domain, or buy a lookalike domain just for outreach?

Some people swear by separate domains so the main one stays safe. Others say it looks a bit shady when a prospect checks you out and the domain doesn't match your site.

What are you doing right now? And did switching either way actually change your replies, or was it more of a peace of mind thing?