No one here is saying it's a livestream you mong, the podcast is not streamed and everything was recorded on-site. While Hololive/Cover is providing the tech, Calli still has to be in the same room as the trio during the podcast recording*. It's why on both episode she appeared in (more pronounced in the first episode she's in) Garnt barely moves around his spot or do any of the gesturing because Demondice/Karen is right beside him and he could fuck up the greenscreen setup that she is sitting behind if he going apeshit. (I know this was mentioned somewhere by calli on her streams but I might be wrong).
And yes, her manager is there, because there's a clip in the podcast Calli first appearing in where the trio acknowledge their present, specifically said manager not amused that Joey the australian man has less computer knowledge than the staff.
*: this is also why they rarely have any vtuber guests beyond Calli and Kson. They have to be physically present, and the only time it's the exception (Ironmouse), it was done on their actual livestream (Trash Taste: After Dark) that isn't podcast-themed to begin with.