Over time, the russian meat dies over and over again, but the person guiding them through radio becomes better and better at pushing the "meat" forward. Push it enough and you can get it to accumulate. Or get it to ambush ukrainian soldiers, get them to take over drone positions, or get them to...wave flags. Flag waving operations are different, because the goal no longer becomes DRG tasks or accumulation, but getting to x or y locality so you can be filmed waving a flag. Understand, that if russians do successfully advance somewhere, THEY WILL NOT MAKE IT PUBLIC. They will keep pushing, keep accumulating. There's no reason for them to publicly alert the enemy's high command. Maybe the unit there is lying to superiors, and by remaining silent, you can get away with it for longer. You have such an example from last summer where an estimate 1000 russians moved past the LOC and dug in multiple localities, DeepState had to publicly break this story for the UA command to react.