I've got bad news.
I personally felt like this episode (the manga chapter, not the podcast) was a small piece of neck bones. Little chunks of meat at the ends but barely anything in the middle (I'm looking at you, Isidrunk) Like yeah, the parts with Skullknight & Dannan, Moonlight Boy showing up, and ISMA TAMING A KELPHIE, WHAT?? all of that was good, but this chapter didn't fill me up like the last one did. I dunno, maybe the frustration is getting to me?
Individual issues of Berserk are called episodes. Also, the "little chunks" you mention actually make up the majority of episode 363. But really, beyond that, the segment between Isidro and the witches was great.
It serves several purposes, like we mentioned on the podcast. The action and comedy are stellar in and of themselves, and they provide a little bit of relief between heavy, dramatic scenes. But Isidro’s quick mastery of the low gravity environment is also a reminder that, for all his goofiness, he’s not to be underestimated. And make no mistake, this is something that will have a pay off at some point in the future. There will be a crisis on the island, and in that forest, Isidro will be able to take on an enemy he never could have otherwise. And I mean yes, maybe even an apostle. The same goes for Isma with her Kelpie of course, but it's odd you don't recognize Isidro's potential here.
It also further develops a bunch of characters, starting with Schierke and Isidro themselves. Their "rivalry" was introduced all the way back in volume 24 (in which he trips on a root and grabs her breasts while falling forward) and has been going ever since then. It's led to a lot of development for them both so far (with Isidro feeling inadequate, etc.), and will lead to more in the future. And I say for both of them because it also shows the limits of Schierke's magic, where Isidro moves too fast here for her to be able to do anything. That fact may not have been lost on her, and it might help her better face a similar threat in the future.
But it's not just them. It helps flesh out background characters too and further establishes what the island is usually like (i.e. eventless), as well as the disruption that these visitors represent. In fact this scene is a direct continuation of the one in episode 344 (even the creepy girl focusing on his crotch is back at it). That’s why Molda is so delighted by these shenanigans. It reinforces our impression of these magic students as disciplined but lacking in real-world experience compared to our crew. Which is also something that might come into play later on. If the island actually gets attacked, these kids would no doubt be powerless to react... unless someone were to rise up and take command. Then they could, all together, show what they can do and fight back.
Lastly, it stopped Schierke from asking more questions about Flora, meaning Miura wants to keep that reveal for later and wants us curious about it, and it provided an opportunity for Guts & Gedflynn's one on one talk about the Skull Knight and the dangers of the Berserk’s armor. And, of course, it participates in establishing that this would be a perfect place for Schierke to stay in permanently, because she's among her peers, and they've bonded through fighting a common enemy. This will make her decision not to stay much more meaningful when the time comes.
By the way, you really shouldn't overlook Isidro and Schierke's relationship. There may come a day when things get serious and he puts himself in harm's way to buy her time, and you'll find it more poignant than you thought. And that will be because all these little scenes throughout the series paved the way for it.