You should be fine. Low power mode is just a state of lower power consumption.
But as for saving battery health, id definitely go on YouTube for in depth tips.
One thing you can do is go into your Settings> General> Background app refresh, And just turn off some stuff u don't need on.
Also Settings> Privacy> Location Services, and jus turn off some unneeded stuff.
Ohhh, Also try not to let the charge drop below 60%, i think i read somewhere keeping it around 80% will help you get the most out of ur battery
My 11 is around 6 months used & the battery health has dropped a whole 10% 😱😭 But I THINK it’s supposed to decrease about 1% a month
so lol good luck to u, again YouTube will do you wonders