Split your password into multiple, partially redacted, reconstructable backups.
Why? Because it's simple. You can physically divide your password amongst trusted guardians without a single point of risk. You can choose your level of redundancy. It's simple to reconstruct. And it's most likely better than whatever your current master password/private key backup strategy is...
Is this secure? Absolutely... there are no libraries, no dependencies, no connections. The code is a single, readable, 117 lines, html file. For the security conscious, this page can be saved and run in an incognito browser, from your local disk, on an air-gapped (offline) laptop. Please disable/disconnect/isolate all screen sharing tools, key loggers, usb devices, cameras, microphones, recording devices (mobile phones, conversational AI home assistants). Ensure your screen is not visible to others. Do not read the passwords out aloud. Do not copy them using the clipboard. Close the browser when finished. Test reconstructing your password to avoid human error.
Recommendations: Do not store backups together, consider separating them physically, geographically, socially, etc. Do not store or transmit them digitally, use a pen and paper to record - take care not to leave imprints on surfaces. Manually distribute. Store them in a safe, secure, robust, non-corruptible, fireproof, waterproof, tamperproof container, under the guardianship of a trusted entity. Choose your own risk mitigation level: Risk = Likelihood x Impact.
Tip: Is your redacted password guessable, or a common phrase? Consider changing it!