Part joke part truth: become a game developer. Since I started to make games I spend much less time playing them. Also sometimes I just have to play more diverse set of games to use them reference for my game design job.
Okay now here is serious note.
> Is it possible to have a "healthy" amount of playing?
Talking from experience - even without taking real drugs into account it's certainly possible to get "unhealthy" amount of anything: reading or listening books / podcasts, or digging into Linux, or even swimming.
Instead of "fighting" some "gaming addiction" you need to try find other interests be it front of PC and in real life. Make it a goal to find something else that also make you happy be it books, DIY, sport or social danding.
Once you have healthy number of interests other than games then not wasting all your life on single thing become so much easier. My personal take on issue of addiction is super simple:
1 - First of all I have a queue of all interesting things I wish to do: films, series, anime, books, podcasts and games. And I add things to this queue once I find something that make me curious.
2 - Also I have a rule to go and check some new things from said queue so I don't stick to one single thing for way too long.
3 - And when it's come to games I also try to honestly ask myself "Am I really enjoying every second of it?" Because some games specifically design to take you into grinding and enjoyment-frustration loop. So why continue to play if game no longer make you feel good?
I understand that some people might have worse problems with self-control than I, but I hope this small piece of my own experience will help someone!