It’s pretty complicated and it’s been a while since i read the layman’s-terms no-maths explanations, but think of it like driving

You’re in a car looking at another car which is driving at the same speed on s road which is parallel to you. You’re both going to look like you’re driving at the same speed and travelling the same distance

Now say that rather than being parallel the roads are at an angle to each other. Say 45 degrees. Now when you look at the other car, even though its Speedo will say the same as yours it’ll look to you like it’s going slower and it’ll fall behind you. After a while you won’t be able to see it out of the drivers side window and will have to look through the back seat window and then the rear window to see it

And the experience in the other car will be the same - they’ll see you as going slower and falling behind them

Nobody’s speed has actually changed, it just looks different from each car’s perspective

If you can mentally change “difference travelled” to “time passing”, then that’s how to conceptualise it