Zelensky (surprisingly) gave more detailed numbers.
Between 60 and 100 Ukrainian soldiers are being killed in combat, and “around 500” are injured every twenty-four hours, Zelensky said
https://www.kyivpost.com/ukraine-politics/zelensky-ukrainian-army-suffering-up-to-700-casualties-daily.html
Yes, but with caveats. It's a random chance that can vary by unit type, e.g. M1 Abrams has about a 70% chance but T-90 about 50%. This applies to all vehicles, even trucks. If the unit makes it's "saving throw" it knows an ATGM has been launched and the direction from which it was launched but not the exact location.
Michael Kofman and Rob Lee dive into Russian military force design and how it relates to this war.
https://warontherocks.com/2022/06/not-built-for-purpose-the-russian-militarys-ill-fated-force-design/
“Anti-tank missiles slowed the Russians down, but what killed them was our artillery.” -- Gen. Valerii Zaluzhnyi, commander of the Ukrainian armed forces
I would be cautious about ascribing outcomes to any particular weapons system or type. Reasons for the Russian failure are manifold.
Maybe Poland is returning to their Warsaw Pact roots by going for an artillery-centric army?
It is a staggering number, and I don't have a good explanation. But if the US decided to supply HIMARS to Ukraine I don't know why they would funnel it though a Polish acquisition rather than giving it directly.
One seldom mentioned aspect of this is that, broadly speaking, the Southern Military District units have significantly out-performed those from the Western MD. The "elite" formations, such as the 4th GTD, have been the worst performers.