4 - 6 Hours on a full charge when gaming is pretty excellent. Even if the laptop is not running, the battery will lose stored charge over time. So if you're charging it full then waiting 3 or 4 days before use, you can expect to lose quite a bit of the charge.
Sounds like your laptop is preforming at it's standards. A solution potentially could be just ordering a second battery and cycling between using the 2 of them. That would only work if you have an external battery though, I know my laptop for example, has an internal battery and while it is possible to get a second battery, It's extremely difficult to dismantle the laptop to install a new battery so this isn't something I could do.