They still have Mach 5 rockets that the US cannot defend against.

Patriot batteries have shot down every missile type that isn't an IRBM like Oreshnik, and those are closer to Mach 11 than Mach 5.

Kinzhal and Zircon have been at least semi-reliably shot down. Iskander is very reliablly shot down. The main issue is that Ukraine just doesn't have enough Patriot batteries to defend the whole country, so the Russians stopped shooting where the air defense is.

They also use a bunch of S-300s as ballistic missiles (a secondary capability to their primary role as air defense) but primarily against cities that don't have air defense. But they're too inaccurate and inexpensive for the Ukrainians to bother attempting to intercept even if they had enough of the appropriate air defenses.

"Patriot batteries have shot down every missile type that isn't an IRBM like Oreshnik, and those are closer to Mach 11 than Mach 5."

Keep lying lol

Do you deny that Ukraine has shot down Kinzhal and Zircon?

Do you have any proof of that?

Their wonderweapons are artisanal products. That Mach 5 missile needs several days of preparations by specialists from the manufacturer before it is ready for launch. In tech terms: it doesn't scale. And such long preparation leaves ample time to destroy launch sites at any indication of preparations for an actual attack. When Russians fired one without a warhead at Ukraine, they made sure to notify the Americans in advance to avoid exactly that.

It's just a PR stunt. Notice how troll farms tried to hype doomsday scenarios, and how little traction such fears got in the actual national security circles.

Ok, but what if the missile gets out of the prototyping stage?

Unlikely to happen. In Russia, all the modern weapons - from Armata tanks to Su-57 stealth planes to doomsday missiles - are mocked as "multiki" (cartoons), because they don't really exist beyond a few barely functional prototypes that are paraded around on national holidays.

All the weapons actually fielded in large numbers are either directly from the Soviet era, or endless upgrades of upgrades of obsolete designs - like their T-90 tank, which still has a fatal flaw that sends turret flying when the tank gets hit. Russian weapons industry has for more than three decades consistently shown total inability to produce anything new. I'd start worrying as soon as Russia finally produced a decent car; that would be an indication that something has fundamentally changed.