MF is pretty straightforward with a camera and lens designed for it. Film SLRs had much larger and brighter viewfinders, and most of them had some combination of a fresnel screen, microprisms and split image focus aids; and the manual focus lenses had long, smooth, throws.
Crop DSLRs have comparatively small/dim viewfinders, no focus aids, and many AF lenses have a poorly damped, short throw, MF ring added as an afterthought. FF DSLRs are a lot better, but all AF cameras - including the film ones - leach some light out of the system for the AF.
A lot of people struggle with AF on a DSLR until they learn how to use it. There are two problems. Firstly, transitioning from a compact introduces a new component. Everything else being equal, depth of focus reduces as sensor size increases. Most compacts have very small sensors and great depth of focus, so focussing accurately isn't too critical. DSLRs have larger sensors and it becomes more important. Secondly, AF isn't magic. The camera doesn't know what you want to be in focus unless you tell it. You need to learn how to select the focus point according to the subject, and/or lock the focus and recompose using a half press on the shutter button or back button focus (if the camera has this option). The aperture comes into play too. Smaller apertures give greater depth of focus, but you have to adjust shutter speed and/or ISO to maintain the correct exposure. There's usually some latitude in good light, but as the light goes down you need to watch the shutter speed and ensure that it doesn't drop to the point where camera shake creeps in (IS helps) or rack up the ISO.