Is there a way to lengthen battery life?

To start this off-- I am no expert and have nothing to do so... this may not answer all you problems at all but

I do know charging more than needed CAN reduce battery life over time from what I understand. Some batteries that I have seen will say on them-- "Overcharging won't do this or that"

So unless its specified or Apple says so, I'm assuming its a regular battery and if thats the case it will cause damage to overcharge it, from what I understand.

You have Apple so I don't know for sure but Android phones will show Every single thing thats using your power.

For instance it will say

Wifi is using 20 percent power consumption and so forth- So see if you can find that setting in Apple and you will find out what takes more power than an other.

Having multiple tabs open could shorten battery life, so maybe only keep the one you have on. Turning brightness down can also increase battery life-

Any form of WIFI turned off could also help if you need some more seconds of life-

Other than that, you could look up more answers on youtube, maybe even get a higher battery from another phone or Apple phone specifically and maybe you could replace it manually? Im not sure if an Apple phone is easy to open but if you can, you could see if thats possible.