If you right click on the progress bar at the bottom of the video, one of the options is: "Copy video URL at current time". (Although YouTube might also start adding extra IDs to that URL in the future.)
That's like asking how to right click on a television. Mobile devices are designed primarily for mindless content consumption and personal data collection so basic functionality is crippled by design
I get that "Use a real computer" isn't helpful though, so I'd recommend getting an app like NewPipe since you can use the "share" button there to copy the video's URL with the current timestamp included to your clipboard or paste it directly into apps of your choosing.
Yeah, I remember that. Specifically what I remember is a discussion on reddit about how a lot of youtube videos have useless stuff in the first ~30% and someone who joined the comments -- wadsworth -- also happened to work at youtube. Apparently with enough freedom to have an extra parameter check deployed to production. Probably around 2012. The parameter I remember was wadsworth=1.
Edit: Got the story wrong. Wadsworth was just a commenter with an opinion and someone who worked at youtube had a sense of humor.
Wadsworth's constant lives on in spirit via SponsorBlock blocking all the intro BS and allowing users to set a timestamp as a highlight with a button to skip to said highlight. I use that feature all the time.
