Russian spin is that UA has only taken the "forward" line of defence and is putting pressure on the real 1st line, Lassel seems to be using pro Russian terminology which speaks volumes! It's wrong to think of isolated 1st 2nd 3rd etc lines of defence, this just seems to be something talked about by western bloggers and are identified from satalite images, between each of those aparent fortified lines are more hidden connected defences such as along tree lines, each has to be cleared and even if there aren't many orcs defending them it still takes time. Ukraine has overcome the first fortified defenses they've come across, they seem to have progressed through a network of intermediate defenses and we seem to be getting reports that they are now pushing through another line of stronger fortified defenses.
As for the losses, this is a particularly brutal war, when you consider the types of weaponry used by both sides, of course the losses are going to be huge, this is precisely why the UA is doing as much as it can to limit those losses.
