A common practice is to introduce services that handle shared functionality.

One common example is, instead of having a shared library that reads & verifies JWTs, use a gateway service that handles this before requests reach the upstream service.

This means changes to your organization's JWT code will only require a redeployment of one service, the JWT Auth service.

But that also for input handling, formatting or simple business libraries? Sure you could implement that as services but that would probably result in up to a hundred service calls for one customer interaction. Maybe it looks clean from an architecture perspective but I can't imagine how that'll result in a good user experience.

Let me clarify because I wasn't clear in the parent comment.

Microservices using shared libraries -> ok

Microservices "suffering" from shared libraries -> not ok.