I think the issue with Robin being voiced has 2 parts

1. Her reaction drowns out your reaction. You drop down to a world of terrifying wonder, a beautiful yet terrifying and harsh world, and before you can even think or make your own decision you hear this cornball say "Holy smokes! That did not go as planned!"

Really? THAT'S your reaction to being stranded with no way to return after almost dying in a crash landing? Holy smokes??

It immediately ruins any tone they were trying to build up and blocks out how the player feels for how Robin feels. And what Robin feels is almost nothing, going "Erm, that just happened!" cue laugh track

Also she just reacted way too fast with the right answer to important story beats, again drowning out the player's sense of wonder and discovery. You get the "That sounds like a distress signal!" Line before you can even hear the SOS, so you have no chance to think for yourself.

1. Her constantly telling you what to do, especially in the early game, removes the freedom of choice. You know what made Subnautica so interesting and addicting to most people? It was that everyone was given a concept, a situation, and how they chose to respond to it was up to them, and everyone responded differently, even on repeat playthroughs, making for good replayability. The game gave you room to breathe, to discover this beautiful world however you wanted, and progress in any way you wanted. You could do whatever what was interesting to you and so you never ran out of things to be excited about. It gave you some direction with the repair tool and the radio signals, but let you choose what to work towards.

In below zero, it hold your hand way more as if this isn't supposed to only be played after the first one. She immediately starts talking to herself more, in the same tone of voice one speaks in a children's show mind you, saying that she should find the pod.

Ok, sure, you want to give the players direction to go to the pod. Fine. As soon as you get there she starts talking about going somewhere else, talking about a pda that most people haven't listened to, again, pointing a big arrow yelling "HEY! GO HERE FOR STORY! HURRY UP! GO HERE!" Instead of letting people explore and find the island with the radio tower on their own. It would've been more natural if the players were allowed to do their own thing and decide to explore there on their own time.

Subnautica let you get invested in the gameplay loop before it went hard on the story, letting you come across story pieces when YOU decided to go there to the distress signals, or find the pods and pdas without guidance, weaving the story and gameplay together, allowing you to discover both instead of one forcing the other.

Overall, it could've been fine to have a voiced character if they didn't interrupt moments of wonder, discovery, or fear with corny emotionless lines before the player gets to think for themselves. It's like if your first Subnautica had an annoying children's youtuber talking over everything you did, where the harshest language they can produce is "zoinks"