I recently got a new laptop, and unfortunately it doesn’t have an option to stop charging at a specified limit in the BIOS. Also, due to this, even tlp cannot help in this situation.
KDE Plasma has an option in Power Managment to set charging limit. But your hardware and your kernel should both support charging limit to be able to set it via Plasma settings.
That is very much hardware dependent. There is no universal solution. In case your laptop is lenovo ideapad or V series (basically any lenovo that is not a thinkpad, since they have another driver and command to do it), you can activate conservation_mode as per arch wiki…or just use the script from AUR (or manually) - conservation_mode.sh - aur.git - AUR Package Repositories