I don’t travel extensively, but have gone on multiple international trips in the last 10 years. Each time, I just prepare to be direct, take my time, and rely on my documentation. I have gotten flagged by Interpol because of my common name and sent to a back room for more investigation. Just stay calm, let them do their routine job, and lean on your documentation to do the explaining. Same way I handle any interaction with police or legal system. If I stutter a lot, I say I stutter and to please be patient.