Israel wont even fly F-35s over Syria, and the US wont fly F-22s over Syria without agreement over that with Russia, and the west talks about the F-16 like it should be the F-35... most western politicians think the F-16 can do what the F-35 was supposed to be designed to do... ie operate over Russian air defence systems and drop bombs on them because they could not possibly detect its presence over them.
You have to ask where these politicians are getting their information from... they think sending F-16s to Ukraine will eradicate Russian air dominance and somehow destroy Russian ground forces. They are sending F-16s in groups of maybe 32 at best...
But why would their advisors be telling them the F-16 in any version let alone the clapped out old models they will actually send to them will be capable of achieving this?
I would guess the F-16 started out as a threat... they thought the Orc offensive would surprise the Russians and force them to the negotiating table with the threat of F-16s as pressure to get a good deal.
But why not threaten with the F-35s? Because this is an exercise in dumping junk and disposing of it so the western MIC can make trillions over the next decades replacing it with new stuff and if they sent F-35s and they failed then they will have to spend trillions fixing it and current sales will dry up once it is revealed to be a white elephant.
Right now the best western aircraft are probably the Rafale and probably the F-15E, but they will never enter Ukrainian airspace.
The Su-57 is literally a whole generation ahead of them.
The F-22 and F-35 are designed to dominate in airspace filled with 4th gen fighters and that is 4th gen fighters... not 4+ gen like the Su-35 and MiG-35.
If any aircraft need upgrades and improved specs it would be the F-22 and F-35 but the former is more likely to be retired early to save on costs, and the latter doesn't even have most of its problems fixed let alone new capabilities added.
Of course upgrades for the Su-57 will be ongoing which continues to raise the bar the entire west has failed to jump... only China seems to be competing... and good for them. They are not psychotic like the west is.