Nope, not true in the slightest. There’s actually a lot of variety in biomes, flora, fauna, characteristics - and a lot of them even have multiple biomes with different life per biome.
What i expect people are complaining about is one of two things:
Planet scanning is boring.
On noes generated dungeons
To the first point, I agree planet scanning gets pretty boring if that’s all you do for 5 hours straight. But there’s a TON of content in this game. Switch it up. Once you’re done with a mission, go explore the planet you ended up on and scan the things. Or don’t. Who cares. Planet scanning isn’t necessary at all. I think a lot of people see that planet scanning gives you a ton of credits and xp, go grind that one thing, and then complain that it’s boring.
On the second point, yes every planet will have a bunch of locations that are like “Cave” or “Covered Crater” or “Abandoned Facility” and such. A lot of them are small resource troves, but the facilities actually feel pretty handbuilt - if you check them out. But I think a lot of people see “Abandoned [whatever]” and think “oh autogenerated content, meh” without checking it out. I certainly have been guilty of that. But every time I actually decide to go in, I’m surprised at how much fun I actually have in those environments, how much environmental storytelling is actually there, and how well built the levels are. I feel like they hand built a bunch of these or components of them and an engine puts it all together.
The reality is that every Beth game ever has used procedural generation. And they’ve been getting better at it with each game. Skyrim felt less empty that Oblivion. Starfield feels less empty, overall anyway, than Skyrim. The handbuilt hub planets are way busier than any location in Skyrim. The procedural worlds feel more empty than skyrim for sure, but it makes plenty of sense, theres still plenty to do, and the amount of planets makes it feel less empty. And overall, there’s a LOT more handbuilt and story content than skyrim - by several factors imo.
I’ll also point out that the procedural content is just flavor. You don’t need to engage in it but it’s there if you want it. This game has a TON of handbuilt content - more than any other Beth game. The faction quests feel like a full game in their own right. The side quests are plentiful and quite deep. Complaining about procedural content in this game feels like complaining about the number of leaves on a tree.