Exactly five of these airframes are capable of flight.

It has been in development as long, if not longer, than the F22. It claims to have vectored thrust (demonstrated in air shows), stealth (if you squint just right), and the most advanced weaponry and avionics known to man (within a given value). Russia claims it to be cheaper, easier to produce and ready for sale to any country that asks.

Well...there's problems with some...most...okay, all of those claims, as typical of Russian hardware.

• There are exactly five of them, all of which outfitted for air shows as opposed to actual combat. These five hand-made examples have zero interchangeable parts, as they are each closer to iterative prototypes than actual combat-ready aircraft.
• here to rain on the "cheap and affordable" parade is the concept called logistics. Even before Russia became the subject of a game of Drone Whack-A-Factory/Refinery, Russia's manufacturing base is still stuck largely in the 1890s overall, with some few select factories still stuck in the 1970s. Russia does not have the machines to build the machines, to build the factories, to build the tooling, to build the factory that could ever mass-produce anything we would ever call "new" or "advanced".
• The SU-57 is held together with wood screws.
• What Russia and China calls "Stealth", the rest of the world calls "reduced visibility"...the same neighborhood as the SR-71 and 117a. Imagine this overweight chungus of a plane in half-assed camo, while carrying a plane-shaped constellation of wood screws, glowing as bright to radars as the sun.

All in all, this craft in't even the definition of a "paper tiger", so much as a "cardboard standee". An "Imagine Russian Might, HERE" sign...as shown by the mirror behind our girl.