Best CRM for cold outreach to Non Profits

Good afternoon!

I'm in the process of setting up a CRM for which I would like to cold call and email Non Profit Organizations around the country from. I have a spreadsheet full of publicly available data from these non profits..so far around 50,000+ of them.

What is the best platform to use for these cold calls and emails? We're a non profit ourselves, so money is very tight. I figured we would use HubSpot, but it seems they have a very strict policy forbidding outreach to anyone who hasnt officially opted in via our landing page.

I would like to to able to do individual calls and emails and gradually chip away at our lists, so we can get an initial user base for our platform.

What's the best way to go about this while keeping ethics and legal in check?

Thanks so much for your feedback!