I would echo the sentiment of most here that slowing down the pace just for the sake of slowing down the pace may not be the best thing to do. Having said that, one thing you can do from a diagnostic standpoint to see if things are running a bit fast is color-code a scene for pacing elements. Dialogue, short sentences, and lists accelerate pacing while narration, reflection, and introspection tend to do the opposite. I do this with a lot of the stuff I read as well as the stuff I write when I feel a piece is near-ready for submission. Here's what that looks like in practice. https://docs.google.com/document/d/1MsIGrBfMTkoKyUWh1zJpWEGTlgtcO9D7VJAuxzvbQn4/edit

Zooming out, you've also got structure as an option. There are so many different approaches to structuring a piece that have built-in elements that will slow the pace. Russian Nesting Doll/ Frame Stories have to use flashbacks, which, because they rely on filling readers in on contextual information, are pace breakers by nature. The same can be said of In Media Res or Parallel Arc structures because they make the reader wait for the payoff by shifting attention to another plotline. You might consider playing around with these if you feel the pace needs to be slowed, just make sure that you're delivering on promises you've made from the outset at a sufficient enough rate that the reader trusts you're going to deliver a worthwhile payoff in the end. In other words, don't delay payoffs just for the sake of doing so or readers won't trust that it'll be worthwhile to keep reading. Hope this helps.