Speed was my priority too, and most Caribbean options take longer than advertised. What helped me was checking how the government handles the due diligence and approval steps. Some countries outsource processing to Dubai for efficiency. A good example is Sao Tome citizenship
https://saotomecitizenship.com/ which promises a six-week turnaround if documents are complete. The process is simple: consultation, application submission, due diligence, donation payment, and passport issuance. No interviews, no language tests, no residency. If you want quick and straightforward, this one is worth considering.