Our kids have done a mix of public, private, and home school depending on where we have lived and their individual needs. We are fortunate to have this level of flexibility.
Most challenging: It's just a ton of work. Doing it well is a full-time job, which is of course why the world has professional teachers.
Most rewarding: Watching the kids really get into certain topics. There is a level of flexibility you can't get in a large group, and your kid can move at their own speed. So if they decide they're super into some topic they can quickly finish the other required work for the day and then have time to dive deeper into their topic of interest. I came home yesterday to find that my preteens spent the afternoon composing original music for percussion ensembles, and it's actually good.
Edit: I know home schooling isn't popular here on Lemmy. There are definitely people who abuse it to the detriment of their kids. But there are good reasons to do it, too: maybe your kid has special needs that school can't accommodate, maybe your kid is being harassed, maybe your kid is significantly ahead/behind their grade level and sees school as a pointless waste of time, etc. And you can get plenty of social interaction with sports, clubs, or just playing with other kids in the neighborhood. It does not have to be a solitary activity, and should not be.
Our public school district offers a hybrid home school program for this. You can do core subjects at home, and then the kids attend a branch campus for classroom-based electives like music or robotics. It's really sweet.