Area-51m R1, bloated battery issue

Greetings to all. So recently, my laptop had an issue with the keyboard in which a couple of keys died and became non-functional. Upon the technician coming and opening my laptop, it was revealed that my battery is bloated. He explained to me that this thing isn't covered by pro plus coverage cause people usually leave the batteries plugged in all the time which leads to them being ruined. 

My question here is, how do I prevent this from happening in the future? Cause I don't want to keep buying new batteries.

Now, normally I understand that you let it charge, once it's full, unplug. The thing is, if anyone else owns one of these monsters, the annual specifically mentions that whenever the laptop is unplugged, it won't use the full power of its desktop components. So in order to get the full potential and power out of this laptop you NEED to have it plugged in all the time while you play games.

I've had this laptop for nearly 4 years now and this keyboard issue and now this battery issues are the only problems I have had to date.

How am I supposed prevent the battery from deteriorating when I need to have it plugged in all the time to be able to play games properly?

Thank you for your time and I hope yo all have a wonderful morning/afternoon/evening/night!