Soldered RAM means you're stuck with whatever you bought.

No. If the RAM is soldered, you can’t upgrade it, period. Chipset support doesn’t matter—you’re capped at the capacity the manufacturer put on the board. So if your laptop came with 16GB soldered, that’s your max, even if the chipset could address 64GB. You can’t add more, can’t swap sticks.

The only way a soldered laptop runs more than 16GB is if it shipped with more than 16GB from the factory. Some soldered models do offer 32GB or 64GB configurations, but you have to buy it that way. No retrofitting.

If you think you might need more RAM later, buy a laptop with upgradeable SO-DIMM slots. Soldered is a trap for future you.