I've been working on this riddle for the past 3 years or so. I think an online literary journal can be profitable if you sell the journal, either by selling the print journal or the epub, pdf, etc files hidden behind paywalls. You need to be careful, however, to secure the files if you decide to go the file route to prevent theft, which you may not be willing to do, and print runs are a $13,000+ upfront expense.
Literary content suffers from the "circular effect" which means that your primary audience will be literary academics, i.e. college professors and students of literature who appreciate it. Basically, the only people who read literature are the people who write literature or teach it. And, if you study literature long enough, you'll realize that literature is political and geographic in nature, at least the ones that the college professors consider important. Therefore, making a literary journal of, say, "Southern Nepalese Literature" will get you more traction, or like "[Name of Journal]: Literature of Southern Nepal", etc.
Judging by my own experience, political poetry is by far the most profitable - I was reading a poetry offer of $70 for a political poem. Other types of poems are hard to publish for any money at all, so there you go. It's pretty safe to say that the more political your journal is, the more successful it will be financially, but the amount of controversy and insults you endure shall increase along with your profits, so politic wisely.
As for social media, basically you need to follow/like/retweet all of the other literary journals and college professors of literature on Twitter or whatever other platform you can find them on. Twitter is actually a good platform to be a literary journal on because you can blast submission announcements, submission closures, and when your journal is out, what events and readings and interviews you're hosting, etc. It's a good way to direct traffic. There are also poetry communities on Twitter/X these days too. Basically you need to network and hobnob with academia for this to work well, following things like the Modern Language Association. It's doable as long as you get your journal into the hands of the right people.