Battery is not charging more then 80% after disabling optimization option

I have contacted support and issue was that my phone was getting warmer so it was not charging more than 80% even if optimised charging is disabled. Before this, following need to be ensured-

1. Please ensure cable used for charging is valid or original one.
2. There should be no VPN or anti-virus app.
3. Force restarting phone may also help.
4. Please check at https://support.apple.com/en-in/HT201678 for right temperature details.

This has resolved my problem and now it is charging till 100%.

Optimize battery charging keeps the device at a max of 80%.

You must turn it off.

Optimize battery is off but still it is taking more time to charge after 80%. Is there any solution for it?

i turned it off and tried. still it is stuck at 80%. i left it plugger for around 4 hrs. to find it still at 80. something is wrong