kinda wish there was a way to set low battery mode on my phone as the default

follow me if ur cool
kinda wish there was a way to set low battery mode on my phone as the default
On my Android, I can go to Settings -> Battery -> Battery Saver to do this. I think iPhones have a similar thing called "Low Power Mode?"
i can do that, it just auto-turns off when it hits 80%! i want it on always unless i turn it off