One-way: use headphones — translation plays continuously. Two-way: mic pauses while TTS plays.
One-way: Use headphones so the mic does not pick up the speaker; you will hear translation continuously. Tab: Open the video in a different tab (e.g. YouTube). Choose "Website / video tab", click Start, then in the picker select that other tab (not this page) and turn Share tab audio on. On Mac, only tab audio works (not other app windows). Use Chrome or Edge. Two-way: Mic is muted while TTS plays to avoid feedback.
On mobile: use Chrome or Safari, allow microphone, keep the screen on. One-way: use headphones for continuous translation. Two-way: mic mutes during TTS. Add to Home Screen (browser menu) for an app icon.