PUBG is not an indie. Bluehole made Tera back in 2011.
Ark is trash. Buggy trash.
Hellblade and Subnautica are really damned good though.
I got ARK last year for for my younger son, he thoroughly enjoyed it, I've tried it a bit, but it's not my cup of tea. I refunded Hellblade after hour and half, didn't like anything about it except for combat (mostly cause of feints), I have Subnautica (again for younger son, he's into survival games), I heard it's a great game, but again, I doubt it's my cup of tea since I find survival/crafting outside of RPGs tedious and boring.
As for PUBG, I guess that's interesting case - I'd say it started as Triple-I, and then when Bluhole bought them it became AA...which frankly is what Triple-I games mostly are, since they fill that slot.
I was surprised I fairly liked Plague Tale: Innocence, I got it mostly for setting, but was cautious about it, since I don't like that type of games (TloU was snorefest for me), but in the end it kept me quite entertained and interested all the way through.
Now, not sure would that be considered Triple-I or AA, since they have publisher, I guess the lines get blury in lot of cases. For instance, Star Citizen is closing to $300 millions, that is AAAA budget, but they are "indie".