What a practical solution. Deeper googling shows that this is possible for many countries (DE, AU, US, UK, FR at least), often called a concurrent or second passport. I wish I had known about this when various countries had been taking their sweet time about getting me a visa.

https://pointstobemade.boardingarea.com/2018/02/22/getting-a... https://www.passports.gov.au/using-your-passport/concurrent-... https://photos.state.gov/libraries/france/45994/pdf/second.p... https://www.service-public.fr/particuliers/vosdroits/F21517 https://www.rapidevisa.fr/actualites/174-comment-obtenir-off...

Learn something new on HN every day :-)