Here’s what I think I’m remembering right from a video I saw a couple months ago:
Ukraine currently has a fleet of aging MiGs which they’ve improvised ways of using some NATO munitions on. One of which is the HARM anti-radiation (anti-radar, basically) missile. Again if I understand this right, when used on their MiGs the HARM missile can only be used in one or two of several modes it has, where an all NATO F-16 can use all modes of the missile.
Also, they have more total jets now, so they’ve got that going for them, which is nice.