Hello again!
Low Power Mode changes how your iPhone works to a certain extent. To see what’s different, than when this feature is turned off, please see: Use Low Power Mode to save battery life on your iPhone or iPad - Apple Support.
Low Power Mode automatically turns off “when the device is sufficiently charged.”
I’ve never heard that having it on all day will negatively affect the battery. The only downsides to this is whatever’s mentioned in the Article above👆.
Take a look at these Support Articles for more info on different ways to get the most out of your battery, both on a daily basis, and during the battery’s lifetime.
👉 Maximizing the battery performance and lifespan of your iPhone.
👉 iPhone Battery and Performance.
👉 About the battery usage on your iPhone.