Some laptops use swappable daughterboards for RAM.

Yes, but it’s rare and usually not consumer-friendly.

A few business laptops (like certain Lenovo ThinkPads and Dell Latitudes) have used removable RAM daughterboards rather than soldering the chips directly to the mainboard. These aren’t typical SODIMM slots, but they are modules you can swap or upgrade with the right part. Framework laptops take this further with entirely modular RAM slots. But most “soldered” RAM is actually soldered—you can’t just pop it off.

If you’re looking to buy a laptop with upgradeable RAM, look for SODIMM slots, not daughterboards. Those are easier to find and actually user-serviceable. Daughterboard designs are usually just a workaround for engineers, not a feature for you.