EMMC 32G RAM Memory Module for Nintend Switch 32G 64G Memory Storage Module For Switch NS Host Console _ - AliExpress Mobile
How to upgrade memory on the Nintendo Switch - YouTube
Digital Foundry says the dev unit for the OLED Switch comes with 8GB of RAM, while the dev unit for the regular Switch came with 6GB. All retail units still with 4GB. :
Nintendo Switch OLED vs Nintendo Switch: How to choose | ZDNET