Also universities will have declining enrollment

Naturally. Fewer people = fewer students. A smaller country would have fewer students, and a larger country would have more.

Enrollment rates matter more than how many are going, and universities will adjust.

pension funds will have declining contributions.

There will also be fewer pensioners to look after, so not as many contributions are needed.

The real problem with pensions is that people are living longer, so they get money over a longer period of time. Adjustments to pension contributions are more likely to reflect that fact.

But we are talking about a lower birthrate, not a zero birthrate. These "problems" are happening a percent at a time over decades... society would have no issue adjusting.