Timeshift is a complete system snapshot and I exclude everything else like the home directory. I am sure you could include the apps, but I do not know where everything is located.
I would do a complete clone using clonezilla even though I have never used it. A clone of my drive is everything, system, apps & files, correct? So after reformatting the entire SSD as ext4 I would need to use the app to place that image from the external HDD back onto the SSD–no need to install LM first?
Sheila