I want to set healthy boundaries for my teenage son, who spends a lot of time playing video games. I want him to indulge in reading and physical activities without implementing strict, harsh rules. How do I do that? Looking forward to good parenting hacks!
This is a common concern among parents. I totally get your worry 
The first thing you can do is set time limits. If you want to play video games, first you have to do a physical activity or play a board game. Make him do house chores, and then allow him to use the computer, but with a time limit.
Trust me, when I stopped treating video games as an enemy, my bond with my son improved a lot. Once I showed interest, asked him what he plays, and why he likes it, he became more open to setting screen time limits on his own. 
What helped us was shifting from rules to routines. Instead of “no games after X,” we agreed that homework, dinner, and one physical activity come first. Once those boxes are checked, game time is his choice. The power struggle disappeared almost overnight.
I set boundaries by implying consequences, not threats. My kids know that if they don’t follow my instructions, they won’t get access to video games or computer time. So now they behave well. 
Believe it or not, kids copy us more than we think. If you start cutting your screen time with more fun activities, they will observe it and try to do the same. It’s hard for kids to get away from video games when parents themselves are on their phones 24/7.
Honestly, if your kid is getting good grades, focusing on his school work, and getting all the extracurricular activities done, then you shouldn’t complain. They deserve a little downtime, too.
We often treat them as kids, but forget they are human too, with real emotions. School work can get hectic and might take a toll on their mental health, so playing video games for an hour or two is not a big deal. Obviously, if they start slacking off in their grades, then you should set some healthy boundaries and make them understand it’s for their own improvement.
Physical activities became easy when you stop promoting them as “exercise”.
Instead, take a different angle. I started walking the dog together, and it improved our conversations so much. Tossing a football, biking together, running errands with them… All of these things will help them cut down on gaming.
We agreed on “no games before bed.” That one boundary improved sleep, mood, and school focus. Sometimes one solid boundary is better than ten strict ones.
Teach them self-regulation. Boundaries are not about strict rules but more about how one limits oneself. Communication is everything.
Do weekly check-ins. Ask them how their school work is going, how they are handling things. Once they start sharing things with you, you can easily imply healthy boundaries and shift them to good habits like book reading, exercising, etc.