If I send a high volume of emails from my primary domain, how can I avoid affecting deliverability for day to day emails?

Over some period of time, using your main domain for sending cold email will erode its reputation. If you don't use enough customization using merge fields (and some research on each lead), then some people will inevitably mark your emails as spam.

Typically this is minimal if your email volume is not too high and your content is relevant to your audience.

A good idea though is to register an alternate domain that you use for cold email.