Rinse rice until water runs clear. Strain out most of the water and add rice to a multi-functional pressure cooker (such as Instant Pot®). Add milk, water, vanilla extract, cinnamon, and salt and stir well. Close and lock the lid. Select the porridge function according to manufacturer’s instructions; set timer for 20 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer’s instructions for 10 minutes. Release remaining pressure carefully using the quick-release method according to manufacturer’s instructions, about 5 minutes. Unlock and remove the lid.
Stir sweetened condensed milk into the rice pudding until combined. Stir in raisins and serve immediately.