No, external RAM is not a thing for laptops.

Not in the way you’re thinking. There’s no USB-C or Thunderbolt RAM stick you can plug in. Laptops with soldered RAM are locked at that capacity for life.

Some external GPU enclosures could theoretically help offload memory-intensive tasks (by moving video memory to the GPU), but that’s not system RAM. It won’t give your OS 64GB of usable memory. Virtual memory/paging to an external drive is a performance hack, not an upgrade.

If you need 64GB, you bought the wrong laptop. Sell it and get one with replaceable RAM or 64GB from the factory.

Future you deserved a better purchase decision.