That sounds weird. I remember when they overhauled the marines for 3rd. They were so poseable and fun. Yeah, it was goofy that everyone's tactical squad was doing non-standard things, but it's entertaining at least. I can see the appeal of push fit and other simplified kits for mass infantry or beginners, but I don't get why they'd go backwards. Either have single pose with a lot of them, or fewer but you can pose them yourself.
Because if they do "pose it yourself" all you get is the shitty crappy tactical marines where you can point the waist a little left or a little right. No dynamic poses. I think you might be confusing what dynamic poses means. Here's the IG combat patrol, they have different poses, instead of just torso on generic legs and point arms slightly up or down. The trouble is that there's some duplicates of the legs but because there's enough variety of dudes running, standing, leaning, aiming, throwing grenades, etc. you get some variety. But these are monopose.

This is the tactical marine squad that is "posable". There is nothing dynamic, both feet are always on the ground, the only pose options you get is the guns slightly higher or lower. These are not monopose, but they're barely "posable".

If you go here to the bladeguard veterans, you'll see the sprues, the legs are not posable, and the arms aren't really posable, so they're monopose. However, if you look at the sprues you'll see there's a bunch of options for gear, what they're holding, how they're holding it, etc. https://www.warhammer.com/en-US/shop/Space-Marines-Bladeguard-Veterans-2020