Audio/video projector connectivity

Hello everyone

First of all, I hope I'm posting in the right place, as I'm new to Reddit.

I currently have a Samsung LFF3 projector, which is sufficient for now, but my parents just gave me (because they're upgrading) a 5.1 home theater system. As you can see, the projector doesn't have many ports, only a micro HDMI port which (according to the documentation) can be used for audio output using eARC technology. This technology is not present on my home theater system.

So my question is: how can I use 5.1 sound with this projector?

Thank you in advance for your help, and please redirect me if I'm posting in the wrong place!