How do you guys play defense? Best defensive formations?

I'm playing on Ultimate mode now with simulation settings (had to tone down the CPU build up speed) but just wondering what are your guys recommended formations to play defense? I can imagine like most players it can be hard to defend as sometimes and it seems like most of the problem lies with how off ball teammates don't mark play their guys. Also certain positons only cover a certain percentage of the field and after that they won't mark. For example, a winger only will mark the attacking third spot but won't track down in the midfield even if the cpu is near him. The CM will only stay in their coded position and won't track in the box to mark the runner.

So how do you guys exactly defend? Do you guys auto switch? Does anyone take off autoswitch and try to manually mark the middle with their CDM/CM?