I would first ask. Do you really need this in your day to day life? I know a lot of companies use this for hiring, but you can still get a job without them.
However if you still want to study them, there are plenty of resources online, like this youtube channel[1].
Taking 2 days to understand insertion sort is fine but you just need to practice learning more often and use the things you learn more often. Even if it's on toy projects.