GDPR-safe rules for newsletter emails

Hi everyone. I’m struggling a bit to figure this out since it’s quite a specific topic. Of course, I could dive deep into GDPR docs, but I thought I’d check in with you first.

In my current company, we have users who bought Product 1, and we sometimes send them emails about our other products (2, 3, 4) from the same product family. We also send some partner/external product emails. When I say emails - I mean promo emails, product spotlight emails, etc.

Do you think sending these kinds of emails, about other products (2, 3, 4) and partner products, but using the Product 1 sender/email name - counts as them giving consent in the first place, or should we handle it differently?

I’d love to hear your perspective, thanks!