I think the most immediate Ukrainian need isn’t for Air to Air combat. It is to do look down-shoot-down intercepts of Russian cruise missiles, which the F-16 variants under consideration should be able to do quite well, with AMRAAMS. This would be to reinforce the Ukrainian air defense system that is running low on S300 missiles.
Or this would be Job #1 initially, anyway.
Russian aircraft don’t overfly Ukraine proper because of that Air Defense system. So I doubt Ukrainian fighters will be tasked with intercepting them.
One of the biggest roles the F-16s could play is in UA mastery of Combined Arms Breach.
https://www.youtube.com/watch?v=ZZ-sCT_maAQ