Ouch that's tough.

As the other person mentioned, self-hosted / federated, secure services for any infrastructure if you do look to found a chapter. Be paranoid about it. Question the security of Matrix. Hell, the best position might be zero tech/data in chud country, which would need to be embedded in the chapter's by-laws with some write-ups by yourself. The reason being that the data could become a kill list or similar. This applies to all data stacks for socialists, it's just riskier in your case.