Starting with a example of the two flavours of open G chords - which one is easier to use?
You'd think the second one? Only three fingers and no pesky little finger to figure out? But if you needed to play D after the g chords, then the first G would have your left hand's ring finger right where it needs to be to easily move the other fingers around the ring finger (which stays in position as an anchor). This is one of many, many, many little shortcuts you'll be learning over the years.
When I show beginners things, I like to stress that a chords is two or more notes - you don't always have to play all the notes depicted (depending on genre and effect you are going for). I usually only play two or three of the notes of a open A - which I barre with the index finger. Unless I need the high e string ringing out - then I play it 'properly'
When I have focussed practice - it's in blocks of 5-15mins. I might do one or five in a day (or none 😁 ). It depends on how I'm feeling - I rarely grind through for hours anymore. I used to, but I think - for me- practicing is best done in short, focused bursts.
Lastly... I've found learning guitar in particular to be a step, plateau, step experience. That is, you grind away walking the plateau and feel like there's been little progress...but months down the line, you go up a step - all of a sudden you can do it. You'd think it would be linear! But no, it doesn't seem to be.