What's a GDPR compliant alternative to Klaviyo?

A manager in my company was complaining about this, that klaviyo just raised prices again this year.
I said I could look a bit into the issue, played around in the email marketing 5-6 years ago (we're working with a klaviyo agency, but they are only promoting Klaviyo).

Klaviyo is not GDPR compliant, and I'm looking for alternatives as my colleague found this out just today.