Hi @AndersonNel,
I would recommend by starting with the digital marketing certification by HubSpot: https://academy.hubspot.com/courses/digital-marketing
Through this course, you’ll be exposed to different focus areas (email, SEO/AEO, social media, advertising) and should get a first feeling for what you want to specialize on. I recommend not overthinking it and simply completing more certifications: https://academy.hubspot.com/certification-overview
You will not lose more than a few hours to each of these, so there’s really no reason not to.
Regarding the portfolio question, I answered this in detail here: Content Marketing Portfolio
The easiest way to land a remote job is very likely through HubSpot agencies. They are often looking for new team members and it’ll be easier to start here than at an actual company that wants to fill a role with an experienced specialist.
Hope this helps!