Google's Live Caption is the most seamless way to get subtitles. It automatically detects speech from any app—YouTube, Instagram, or even recorded voice notes—and displays it as text on your screen. : Press your phone's Volume button .
If you're watching a video in another language and need English subtitles, Android's (available on Pixel 6 and newer) can translate captions in real-time. Android subtitles English
If you have video files saved locally and need external English subtitle files (.srt), third-party apps are your best bet: Google's Live Caption is the most seamless way