Hi,
Looking at the motherboard in a SSD replacement [https://www.youtube.com/watch?v=OonFKhVF8pE|video] for the laptop there doesn’t appear to be any extra SSD connection types there i.e. M.2 or sata.
One option that you may want to think about if you want to have extra storage in the laptop, is to insert the largest capacity SD card that you want, into the card reader and leave it there permanently and configure it as a storage drive.
It is unobtrusive and out of the way and also it is nearly as fast as a SSD as well. One downside is if you often need use the card reader for other purposes i.e. copying images from a camera’s card etc.