You can deploy containers in a "serverless" configuration, if you're not actively managing the underlying fleet and scheduling (eg, Fargate). FaaS is just one kind of "serverless" computing.

Most of the modern "serverless" systems either operate with containers, or are just mounting your FaaS into a provider based container anyway.

Containers with provider managed infrastructure are really just "process as a service", which often are a better match to your software than "functions as a service".