I would argue k8s is overkill for this and the wrong tool for the job.
Honestly I would never target 100% uptime. Ubisoft, Microsoft, Blizzard, EA, valve, Epic spend billions collectively on online services and still have unplanned outages.
You can get a very cheap VPS from Heizner and you should run your game server there. You get proper cooling, networking, and support if something goes wrong.