My goal is to study for 300 hours (coding problems, behavioral, and system design combined) before I start applying for companies.

Is this overkill? Is it enough?

I put a "stop" on my studying since I know there will always be a question that's a "got-ya" or some extremely hard Leetcode question that require some obscure algorithm from college that had 1 figure about it.

What's your background so far?

By far the easiest "way in" is to grab a degree from college / university, and look around at intern / graduate programs. It's certainly not impossible to get in through other means, but I certainly wouldn't sink 300 hours of effort just in the hope of getting something.

There's also no one set time period, even if this *was* a good way to get your foot in the door. Some people can pick things up near instantly, others will take that 300 hours and still barely be able to get their heads around the simplest concepts.

No matter how many hours you’ve spend so far, you will suck at your first job at least to some extend.

True experience comes from a true job.

300 hours of programming for a janitor will leave a very different effect than 300 hours of programming for a sysadmin/automation specialist (or how the kids like to call it nowadays - devops).

300 hours is not a factor. what you learn to do is.

Set your goals straight. "I will study really really hard for 2 weeks straight" is a weak goal.
"I will learn to build and understand a solution X using tools Y and Z without using SO" is a better goal IMO. Will it take you 300 hours to build it? Maybe, IDK. Will it take you 13 hours to craft it? Maybe, IDK, and IDK what will you be doing with the remaining 270 hours then...

Don't focus on time. Focus on what you achieve.

You are right, you will not learn everything. But you don't need to know EVERYthing to build a well-running soft. You just need to know enough to achieve the goal AND know where to look when you need more.

The "spidey-sense" will come with experience. You'll understand what I mean a few years after you "enter the matrix".

For a single interview, the first 20h concept would be enough to use for this.
But then, there are no hard and fast rules for how many hours you should put as not everyone learn at the same rate or understand things as easily as others.
I would instead focus on the outcomes, topics and then practising over putting a certain number of hours (see also deliberate practise).

@AlmondSauce Hey thanks for the comment. I graduated back in 2016 from a UC (University of California), and am looking to go for the big fish. I did pretty bad in college, so I'm trying to level up and get into a top tier company or somewhere with a high total compensation.