Portable backup power that can handle summer heat

So I have a Netgear Nighthawk M1 router that I use to connect my Thinkware U100 2ch in my 2021 TRD OR DC SB.
I’m looking for a portable battery that can power the hotspot for a couple of days. I don’t want it hardwire and I could keep it connected to the USB port to charge while driving. And charge it at home when it needs a full charge.
I know the truck has its own hotspot but that turns off when the truck is off. So I’m cancelling that service.
The hotspot is basically used for the camera to send me notifications or the occasional live view while parked. And the occasional grandkid connecting their game consoles.
With summers hitting the 100’s and some times 120’s here in Cali. I don’t want something that might explode while the truck is sitting at the parking lot in the office. No shade at all.
I’ve been googling and looks like a LiFePO4 might be an option. But all I find are the size of a car battery. Not really portable.
The dash cam is hardwired. And so far it stays on for a couple of days with no problem. So the backup is only to power the hotspot.
Do you guys use something that might cover my needs and still be safe in the heat?

 

Why not add a solar panel to charge/run your necessary needs, kind of like running a refrigerator. . A battery can only do so much with a single charge.

 

Larger power requirements require larger storage capacities. That just current technology. Have you considered a dual battery for the truck?