My Windows 10 laptop lags when on battery power

These details may be useful, I’ll try to specify every little detail about the issue that I can remember:

- Summary of my laptop’s specs: ASUS TUF FX505GE, i7–8750, GTX 1050Ti 4GB, 8GB RAM, SSD+HDD, Windows 10 Home Edition SL

- The laptop is still relatively new, just bought around 1 month ago but the issue started since around last week. At first, there was no issue at all.

- The lagging issue occurred whenever I unplugged my laptop from the charger, 1–2 seconds after Windows automatically switch the power plan to Power Saver mode. Suddenly, the cursor apparently disappears. When I tried to move the the mouse/trackpad to get the cursor to the bottom of the screen to show the taskbar (I hide the taskbar), I notice from the taskbar opening animation that the OS is lagging very, very bad. I also confirmed that it is lagging when I hit the Windows button and saw that the start menu opens up very slow and jagged.

- Related to the above, I’ve tried to fiddle with the Power Saver plan and the overall power management settings in Windows to no avail. Also have tried to reset the power plan settings to default.

- Still related to the above, I tried to stop Windows from switching automatically to Power Saver plan when unplugging the charger but I can’t find any helpful article in the internet.

- Plugging the laptop in to the power socket after the lagging appears does not solve the issue.

- When it is lagging, the only thing I could do is to fire up Ctrl+Alt+Del and restart, with the charger plugged in since booting up.

- During the Ctrl+Alt+Del screen (I don’t know the proper name for it, it’s the menu that is displayed after you hit the three keys that shows the option of Task Manager, restart, shut down, etc), I noticed that the cursor is there and I can move it smoothly without any lagging issues

- If I log out, the lagging issue is gone in the login screen. However, after signing in to my account again, the lagging issue comes back even after I plugged the laptop in.

- I have all the latest updates from the Windows Update, and also made sure that all the drivers are up-to-date.

- While researching for this issue, I found that the laptop battery status says “plugged in, not charging”. I managed to solve this issue after searching through the web but the main lagging issue still persists.

- Because I very rarely travel with my laptop, most of the time I left the laptop at my desk. However, I always plugged it in to the power socket even when the battery is already full (looks like this is the cause of the “plugged in, not charging” issue above).

- I have also uninstalled the Windows-related softwares that came with the laptop from ASUS, but still have the issue.

- I haven’t ruled out the possibility of any hardware-related cause because I haven’t tried the reset Windows option, but somehow all things are pointing out to software/OS-related issue.

This issue seems to be very specific and I couldn’t find any topic about this issue in the internet. It’s very annoying when I have to use my laptop while traveling.

Any help or insight is very much appreciated. Thank you.