Tadpole Scout Ray Chassis

Make the Skat chassis collapsible so the Tadpole can pass through narrow caves, right now, it simply clips through the geometry. Indeed, with its wings folded, the craft moves more slowly and is easier to control, whereas deploying them increases its speed.
Furthermore, modular upgrades—such as the “Scout” chassis—can be installed, allowing the craft to skim just above the water’s surface at high speed for rapid travel.

Or you could use it as intended, detach from the chassis to explore tight spaces

There will be a huge cavern with several smaller ones branching off from it
it’ll be more convenient to dock and swim in than having to disconnect every time.

So don’t constantly reconnect and disconnect, just use the scout chassis when you’re outside the cave. You’re asking for additional game mechanics because you’re not willing to use existing game mechanics. You have to realize how ridiculous that is.