why your iPhone SE battery drained, here is one of the reason

I just replaced my iPhone SE 2017 battery 2 weeks ago. I found my battery consumed much than before, and happened to find the reason is , after replacement of battery, my iOS 14.1 periodically DISABLE the "Low Battery Mode" (setting->battery->). feels like every 1 or 2 days.

What I'm doing? I am unable to do anything, just check this setting every day. if iOS changed it, I just ENABLE the "Low Battery Mode".

but I'm planning to continue using my iPhone se 2017 for 2 years. that means I will have to combat iOS for 720 days😓😓😓