When I hear about ram being soldered, I think of cheap computers with the memory permanently attached to the motherboard for planned obsolescence and/or cost.

The current mac silicon has memory integrated into the one chip that houses the cpu, gpu, cache, and memory. This approach has pros and cons, one of the biggest cons being upgradability.

It would be great if something like 64gb was stock for the prices they charge, but the fact I can run my laptop for days without it getting hot gives them a pass in my book.