Re: focus. Most cameras focus on shutter button half-pressed. Learn to use this by focusing first (with a half-press), framing, and then taking the picture by finishing the press (not doing a complete press again as that would reset the focus point).
Some cameras let you have a focus button different from the shutter button. This can be super useful and can become natural after a little while.
Or even use manual focus. Want to do "artistic" photos? Get lens with wide aperture (below f/2), it has very low depth of field, so you can focus on your subject and have blurred background. After using "normal" cameras all my life, I've recently (less than 3 weeks ago) bought cheapest mirrorless camera and bought f/1.2 lens (50mm without zoom, those are cheapest lens there are). First photos of my dog were so sweet I instantly fell in love with that camera and lens.
I was going to ask the stupid question "why bother with special lenses to introduce unsharp parts if you can just destroy details in software still anyway" but I think I realized the answer, in case anyone else has that question also: introducing it later depends on knowing which parts were further away. Pictures (typically) don't have depth/distance information for each pixel.
Some cameras let you have a focus button different from the shutter button. This can be super useful and can become natural after a little while.