You could try posting into more established communities like Tabletop / DND or Trading Cards. It's hard to start your own community and get people to read and post in it unless you have a decent following or know people to invite in there.

Outside of that the best advertising you can do for your content is to take the time to read, vote and comment on other peoples posts. Put your name out there in other ways that just posting. Hive is a community and community is built through engagement.

Differentiating your content could also be a good idea. If you go hard on MTG it might not be that incentising for people to follow you unless they're big on MTG themselves.