>>64224623
Oldass flak-jacket like pic related are obsolete and weight a ton.

We already got FAR superior alternatives in the 1990s:
the Armor Carriers, AKA "Full body armor vests", that compose a soft armor jacket + additional attachments + hard plates in front and back.
The US "Interceptor Body Armor" and the later "Improved Outer Tactical Vests" are prime examples of this, and just about every single nation has had their own armor vest variant for the past ~30 years or more.

Yes, Ukraine also started issuing a soft armor vest with plates as standard issue equipment years ago, and many countries did ship them their older stuff to back them up as well, hence why you see Ukrainian bois running in Ospreys, sometimes even PASGT.
But as usual, troops either don't want to wear them, simply because of "muh comfort" / "it's not COOL!"... or there's not enough of them to equip everyone. The Call Of Duty culture seriously brainwashes people, while the frontier operators obviously want to minimize their gear and indeed tank a few AK rounds to the chest if SHTF.

Yes, the modern (post-2005) "flak jackets" are indeed lightweight and flexible. I used to run around with one 15 years ago in Armeh exercises, and you don't even notice it. Didn't get plates back then, but these days a single NIJ Level III multi-hit rated plate can weight only 1 kilogram a piece, which is nothingburger.