These are just my opinions fwiw:

My strategy is to budget for more RAM than I need (16GB should be a minimum honestly for an x86 environment). For laptops I personally don't update the memory, so I feel that soldered memory is fine.

I would suspect the cracked solder joints would be due to people dropping their laptop (indeed there have been issues with manufacturing as well). If you have bad solder joints on memory due to poor manufacturing, how could you trust anything else on the main board?

I would avoid soldered SSDs though.