Pretty straight forward - we have a group of internal leads that we want to send a batch of emails to, but preferably would like them to get it quickly (over 1 or 2 days) versus it being spread out since there's about 15 emails and that would take too long.
Is there a button you can press or an action you can take that pushes the next email in the stream, instead of having to set up a cadence?
No, you cannot do this.
There are some threads on getting the first email out immediately and then putting the lead in the Stream. In fact, I wrote about this a couple of threads ago.