Ideally you buy a 32gb kit. Even buying the same make and model does not guarantee it will work without issues. RAM is sold in matched kits for a reason. It might work but you are doing your own testing. Also if you are thinking of going from 2 sticks to 4 you are more likely to be limited to a lower speed.
See odd man out section here https://forums.tomshardware.com/faq...y-ram-and-xmp-profile-configurations.3398926/