NEXT TO is on the side of something.
If I’m watching TV and you’re standing NEXT TO it, it’s not a problem for me.
When you sit NEXT TO someone at a table, your elbows touch sometimes.
If you’re standing IN FRONT OF the TV, it is a problem, because I can’t see the screen. So I’ll have to ask you not to stand in front ot the TV.
If a tall person is sitting IN FRONT OF you at the theatre, you may not see the whole stage. You will see the person’s head instead.