Don't give them f-35s. Give them Su27s, Su25, Mig29s that are currently in NATO inventory - all of the old Warsaw Pact nations still have those with upgrades.
So give those to Ukraine and replace them in NATO inventory with F-35s (or F-18s, F-16, F-15). It would take time for the ex-Warsaw Pact nations to train up on the new jets, but they have time.
Ukraine, by contrast, could make use of donated Su-27s, Mig-29s, and SU-25s today. No need to train up much, just get up to speed with whatever upgrades the old Soviet era NATO jets have that Ukrainian Soviet era jets didn't.