I saw a tip on the fediverse which, annoyingly, I cannot now find. If I do find it, I will link it here.

Basically, it said:

Have a look at TLP for improving your laptop’s battery life

TLP

According to its documentation

TLP is a feature-rich command line utility for Linux, saving laptop battery power without the need to delve deeper into technical details.

I installed both TLP, and the optional Radio Device Wizard package, with:

apt install tlp tlp-rdw -y

Looking at GNOME’s battery monitor immediately before and after, the predicted battery life for my machine jumped by just over 50%.

I’ll have to see how it pans out but, if it’s anything close to that, wow, what an improvement, for one simple command.

Thank you linrunner!