BG3 is really over the top, but it's not an outlier - BG2 starts with escape from the dungeon, KOTOR1 starts with escape from a ship under siege, Mass Effect1, 2, 3 starts with more or less a cold open, Arcanum starts with our zepelin getting shot down, etc. etc. etc. Most RPGs moved away from understated openings to bombastic hooks a while ago.
Narratively I don't think this is a terrible idea - you want to start where the story gets interesting, and capture by Mindflayers is the inciting incident which brings all heroes together. And after the escape there is opportunity for downtime and calmer exploration in an unfamiliar wilderness. I take issues with storytelling itself, but as far as big picture storybeats go, I don't think it is unsalvageable. It's been done well before.
Sorry to nitpick but in BG2 we start as much higher level characters and it's a dungeon in a city not a burning Mindflayer ship hurtling through the realms being attacked by Dragons et al. I don't think that an understated introduction implies an uninteresting story. BG1 did a good job in that respect that once you leave Candlekeep there is a shocking event and you are left on your own in the wilderness to undertake your quest.
