I reviewed your post and I understand that you want to limit the battery charging to 80% and unable to find the option in the BIOS.
Don’t worry, I assure you I will try my best to get this sorted.
I would like to inform you that if the option is not available in the BIOS that mean that you computer doesn’t support that feature.
You can keep the charger plugged in always when you are working on the computer and it will not affect the battery life. The battery stops charging automatically when it is fully charged, and your computer works on the AC power.
I hope that answers your question and you have a great day!
P.S: Welcome to the HP Support Community 😊
If you wish to show appreciation for my efforts, mark my post as Accept as Solution.Your feedback counts!
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".