This is ignorant and I’m not trying to be rude by saying that (I’m being nice with my word choices) Let’s look at the following sentence:
“This Sukhoi aircraft is just stupidly stupidly overpowered which directly implies it's range will be limited”
Range has nothing to do with power. The biggest factors in any aircraft’s range is fuel capacity, drag and engine efficiency. The goal is always more power, because more power means higher T/W ratio, acceleration, rate of climb, and maneuverability. More powerful engines also allows for more avionics, and more power for those avionics which equals better capabilities.
I’m almost curious how you deduced the cost and maintenance of this aircraft. If anything this should be, in theory, an affordable aircraft if enough are built. Almost like a modern day F-16 but more capable and ‘stealthy’. A basic and rational way to look at it is: a single engine is cheaper to purchase then two engines, operating a single engine aircraft is also more economical; both in terms of maintaining and fuel economy. Then comes the size of the aircraft, smaller aircraft use less raw materials, it also takes less time to machine parts or produce carbon infused parts, less time means less cost and quicker production.
There is also a very interesting thing about this aircraft, it appears to lack horizontal stabilizers. This reduces its RCS, weight and cost. RCS is reduced because additional surface that create corner reflectors are eliminated. Now with weight, omitting horizontal stabilizers reduces weight because engineers eliminated a control surface and all that comes with it: actuators, wires, motors and hydraulics that move those surfaces. Cost is saved because you simply use less parts. (less parts, less maintenance, less parts less acquisition cost). A thing to note with TVC engines there is little need for horizontal stabilizers since a variable geometry nozzle can give similar or better pitch authority and aid in yaw.
