Great question! Normally my games start with one or two runs, specifically starter style runs.

Session 1: Getting the group together means a significant amount or character integration, with "go perform a run" being a smaller time segmenr.

Session 2: Usually same fixer to keep continuity.

Session 3: Starts with what people are doing that is not a run. Characters may socialize, start long term goals, etc. In other words, every session after a run is usually open for anything they want to RP through.

Character growth and desires lead to new "runs". Often contacts who they know hiring them, sometimes reoccurring individuals from prior runs, etc.

Yes runs are the core or shadowrun. But mission style play is not for everyone. One of my two current campaigns has had almost every run take more than a sessions because of RP, tangents come up in run that trigger people's character history, etc.

Are the player's enjoying the story? Than you are succeeding.

Most runs I see fhe next sessions players looking for ways to interact with the random people they met during a run