What is a good battery saving mode application?

I'd like to know of a good program that will automatically enable battery saving mode each time I holster the KEYone, and disable it as I remove the phone from its holster.

Thanks!

bump

Have you tried something like Tasker or Automate?
I don't know whether they would work in this exact case, but it's probably worth checking out.

Thanks, I'll look into those!

No luck yet.

I'm surprised at how difficult this is.
I've looked through the phone and checked for holster settings there as well, but I found nothing. I had expected to see the usual things like set ringtone/vibrate/auto answer when holstered.

Do most android users not use holsters, or cases with magnets?