Which platform you recommend for cold emails?

If you know whom to send, then sendgrid. If you don’t know whom to send and want to figure out leads, use Apollo.

Thanks for recommendation. Isn't sendgrid reputation not the best? Also, do you have any idea about open rates and other metrics of sendgrid?

Outplay, Instantly, Lemlist, snov, First sales

Less expensive option: Lemlist, Snov, Apollo, MixMax Entreprise option: Groove, Outreach

Bulk or targeted? Marketing / CTA or seeking response?

Bulk marketing.