Ubuntu 24.04.01 LTS drains battery while shut down/not in use. What could be the issue?

I am on Ubuntu 24.04.01 on a Lenovo (purchased 3 months ago).

I usually have more than 75% battery when I shut down the laptop and use it on weekends.

Off late I observed that whenever I boot the machine next weekend, the battery in around 8%.

The only difference I sense is 1/ updates and 2/ KDE Connect that I installed (after which this issue is noticeable).

What could be the issue for battery to drain when not in use and specifically being shut? How can I fix it?