My experience is that most podcasts can be sped up to around 1.2x without any issues. Podcasts that have an interview or conversation format can be boosted to 1.5x, and have their silences trimmed as well. It’s important not to trim the silence on podcasts with one presenter such as Hardcore History as the pauses are just as much a part of the monologue as what is said. The excellent Pocket Casts app allows you to set up the specific parameters on a per-podcast basis, so you don’t need to spend time changing it as you jump from cast to cast.
I jokingly suggested that the creators could speed the podcast up to 1.5x to begin with in order to get their revenge on me. Thinking about it more, podcast creators could add subliminal or ‘hidden’ messages to their recordings that you only hear when you slow it down, kind of like the mysterious and mythical additions to 60’s and 70’s vinyl. Maybe they already have?