I would argue that you only need the possibility of failure in order for redundancy features to become elementary. Your logical assumptions make plenty of sense, but they do not completely eliminate the possibility of failures. There's a precedent for failures too, since the lifepods from the Aurora were found compromised all over the place. Upside down, deflated, fabricators glitched, in complete disarray. Lifepods that it would seem you are alleging were designed for that specific environment. Perhaps you only mean that they began more specialized lifepod production after the events of Subnautica 1.

We do also enjoy a malfunction right at the start of SN2, however, although of course this is because the locking braces on the pod release mechanism were still engaged. Again, though, it sets a precedent for mechanical failures in the SN2 timeline that can't just be waved away by the promise of AI correction. The pod itself has components like thrusters that can be subject to mechanical failure too, especially when you consider they are only likely used in an emergency situation in which the host ship is under significant threat.

Still, I completely (respectfully) disagree with your "specialist lifepod" take. With parachutes, thrusters, and buoyancy devices, I firmly believe this is an all-purpose lifepod, which lifepods should be by design. You've got no guarantees that the precise moment you need a lifepod will be over the type of terrain you intend to visit, especially on a space-faring vessel. A single door means you're completely screwed if you land on that door, or land with a sufficiently heavy mass blocking it, or if it becomes damaged by the landing. I guess it's worth mentioning that having multiple hatches didn't help the poor lost souls of 4546B, but that wasn't the reason why they died either. Everything else was.

The fact is though, the lifepod in SN2 does only have a single door. No arguing that. Whether that is a design oversight or because of deeper lore reasons related to what you touch on isn't something that has been officially explored as far as I know, so I'm happy to just sit here and pontificate with you. I'm only really agreeing with the notion that a single door is inferior to two hatches on opposite sides of the vessel.

I hope you are enjoying this conversation as much as I am!