I suppose in my mind AAA refers more to certain group of publishers and parent companies. A certain way of structuring companies and doing business. As supposed to a metric of the budget needed for a game.

I'm not sure if you could call Talos Principle indie. Croteam is an ancient company (of Serious Sam fame), they sold out to their publisher some years ago (Developer Digital). Wikipedia says 42 people, that's about the same ballpark as Wube (Factorio), way smaller than Coffee Stain (123), which yes vibes heavily indie (Goat Simulator!) but is part of Embracer Group.

If you look at Developer Digital and Embracer group they're not really that small -- certainly not smaller than CDProject Red, which is very much throwing AAA money at their projects and definitely had their own big business culture fuckups. They're simply more distributed, instead of orchestrating one or two big projects they have multiple studios working largely independently on small to mid-sized projects. Talos and Satisfactory are AA scale.

Is Wube indie? Well, at least at the start they were, growing with Factorio's early access. Still independent, as far as I know. Budget-wise they're certainly not operating on a shoestring, though... you also have to take into account that they're taking their sweet time for everything. Also AA.

A would be stuff like Celeste. That's a broad category, I wouldn't really call anything B unless you don't have separate coder, writer, sfx/msx and gfx. Maybe toss the writer but anything under that and you're smaller than minimum demo group size.

All this is to say: Can we please stop dividing the industry into "AAA" and "Indie". CD Project Red is independent. They're doing AAA. One is budget, the other is whether the studio has a corporate overlord lording over multiple studios. Game quality is a third measure. System requirements yet another: Factorio has no issues melting your CPU even though it's highly optimised, then you have B-budget projects which melt your box because the dev has never heard of polycount and a background prop toothbrush has 400 quads... per bristle.