Long time Mac and Hubspot user…
Hubspot works flawlessly on the Mac as it is a web based application as mentioned above. They do have a Chrome extension that allows you to use Hubspot features in Gmail. And as mentioned above, you would need to have gmail for business. That would allow you to use your custom domain for your email.
Additionally, having gmail connected to your Hubspot account allows you use the calendar functions for scheduling meetings. (This may be behind some premium Hubspot functions).
I know that Hubspot has similar connectivity for Outlook though I have never used it. Overall, the switch to Mac usually treats most people quite well. I would not consider trying to use parallels especially if it’s just to send emails. That will drive you insane. Best of luck.