I’d say these are both pretty extreme perspectives. The F16 is not going to be the wonder weapon that leads to instant victory because Russia still has a lot of anti-air capabilities and the F16 is not a stealth platform. It will however have a role in countering their air raids and long range missiles.
While there are some parallels to the trench warfare of WW1, the constant capture and subsequent loss of ground is not what’s been happening. There is (slow) progress being made at multiple fronts. I’d say a more accurate comparison could be to the allied breakout from Normandy in WW2.
In any case the F16s will be a valuable weapon in Ukraine’s combined arms.