i think its normal nowdays.my laptop also same. can charge up to 100%( but actually just 80% from designed capacity).
tesla car also same. their software limit just 80% charge unless u want to travel more longer so can charge up to 100%.

old phone, mybe they still dont have this feature yet. i also use accubattery to let me know if its charge to 80% and give me notification on my smart watch, so that i dont overcharge it.
same when i went to sleep, i set the smart plug charger , to turn it off once the battery around 90% full.
i only full charge it when i feel i need to use phone more longer.

the bold part... that's what i've been wondering about... I never saw any phone that charged to 80% only and stopped at that point. (meaning the battery bar/percentage only show 80%).

hello, I have problem with the audio recording of the WhatsApp as it won't record my voice.... I have tried to restart the phone , reinstall the WhatsApp but still it can't record my voice for the voice message.... any clue ?

Maybe your phone microphone spoiled already????

I dont think so because only happen on WhatsApp voice message recording. The other apps are working fine. I have tried restarting and reinstalling WhatsApp but still fail.

Try another plug