A /64 is more than enough though to prevent most casual attempts at entry; and does force more work / enumeration to be done to break into a network and do damage with. I'm not saying the privacy extensions are the greatest; but they do work to slightly increase the difficulty of tracking and exploitation.
With a /48 or even a /56; I can subdivide things and hand out several /64s to each device too; which would shake up things if tracking expects a /64 explicitly.
I actually use /55s to cordon off blocks inside the /48 that aren't used too. So dialing a random prefix won't help. You'd be surprised how often I get intrusive portsweeps trying to enumerate my /64s this way...and it doesn't work because I'm not subnetting on any standard behavior.
I run both because of this; and because SLAAC enables features in Desktop OSes that offer some level of additional privacy.
For example; Windows can do "Temporary IPv6 Addressing" that it will hand out to various applications and browsers. That IPv6 address rotates on a periodic basis; once every 24 hours by default; and can be configured to behave differently depending on your needs via registry keys.
This could for example, allow you to quickly spin up a small application server for something; like a gaming session; and let you use/bind that IPv6 address for it. Once the application stops using it and the time period has elapsed; Windows drops the IP address and statelessly configures itself a new one.
I get a free /64 and /48 directly from Hurricane Electric using their TunnelBroker and use PFSense to deploy that v6 locally on my LAN. Everything in the house has a v6 and is protected by the necessary firewalling too.
This is why I use PFSense and Hurricane Electric as a v6 tunnelbroker. I have working functional IPv6 with SLAAC and DHCPv6 and full Routing Advertisements on my LAN running side-by-side so that no matter which the device implements how poorly; it gets an IPv6 address and it works and is protected by the firewall.
You would be surprised how hard it can be sometimes to source batteries due to shipping rules and regulations; as well as the general difficulty surrounding just building your own battery pack...which can end badly if you aren't an electronic engineer or similar professional who knows exactly what they are doing.
Either Linux has no idea what your battery is telling it; or your battery is just...toast.
Let's just hope for your sake it's just a funny linux bug. Replacing specific laptop batteries can be a tremendous pain if you can't find a specific cell that works for your device.