it’s possible but it requires microsoldering experience and equipment. if the module is still functional, but the flex cable is bad, for example, you could cut off the module and solder onto a replacement flex (may have to be an OEM flex, but I’m not sure).
it’s a pretty intricate repair though and definitely isn’t a DIY process.
also it depends on why the face id isn’t working. I only detailed one explanation, but if it’s something on the motherboard for example, you’re getting into even more dangerous and expensive territory. and a lot of places that I know of don’t offer the same kind of warranties on liquid damaged devices because depending on how bad the damage got the device could have a heavily shortened lifespan.