There are no possible alternatives to US based services unless you enjoy extreme restrictions on speech. Europe has become a big no-go zone for speech over the past decade, they're outright hostile and authoritarian about it (with only a few exceptions among European nations). And the direction re liberalism and human rights in Europe is overwhelmingly hostile toward speech. And for South America, Africa and Asia you can entirely forget about it, there are no reliable speech protected locations in any of those.
Social media is trending towards regional balkanisation. Governments are clueing into the fact giving everyone including foreign states free reign to broadcast to, and manipulate, their constituants is a bad idea. Just look at what happened in the UK recently with the riots. Twitter's days are numbered there.