The principles of investing in private companies, whether in a primary round or a secondary share sale remain the same - there’s no guarantee of timeline for exit, and investing in private companies is inherently risky. A full, traditional exit might not happen for a number of years, if at all.
The majority of secondary investment opportunities on Republic Europe will be for late-stage, well funded businesses, backed by some of the best-known funds in the world, so you may be able to find rumored exit or IPO plans or timelines in the news or in a company’s press releases, however these are not verified by Republic Europe, and you will need to assess any such information on your own.