It's pretty mid nowadays, nowhere near the levels of the F-22 or F-35. But the F-16 C, D or MLU versions are in almost every way a very modern fighter. Russia does pretty much the same thing, but while an upgrade F-16 is called a 'block 50', an upgraded SU-27 is called an SU-30 (or 34, or 35). They're basically all improved versions of 1970s planes.

The SU57 and Mig-35 are basically non-existent, if not actually so.

The F-16 is absolutely not the best fighter out there anymore, but it's hardly a pushover and at the very least on par with what Russia is fielding.

Yeah, that's the theory. Russia had been using the planes to bomb a Ukrainian beachhead from an area that would keep them out of range for the Soviet-era systems Ukraine has in that area, so Ukraine moved a patriot system there, switched off. When the Russians flew in and they got detected on long range radar, they turned on the patriot and fired.