While I would much rather see medical kits distributed to Gaza today than bombs, this could (and should) be accomplished not by converting F35s.
Dismantle the F35s, and drop supplies with a C130 or other military transport capable of airdrop, which will be VASTLY more cost/fuel efficient, thus allowing you to do a lot more of it than you ever could with a fleet of F35s.
Which I'm 95% certain is exactly what the other folks you're arguing with are suggesting.
Dismantle the F35's: sure. Once the victims they created are safe.
But if the F35's were used to murder, they can be used to rescue, too. So do that as fast as possible.
In fact, turning the F35's into medical-supply dropping devices immediately would have another very, very important impact: it would be making amends for all the death and calamity their warrior narcissist pilots, who have spent their lives learning to murder efficiently, have been causing.
We paint the F35's pink to make amends for the murder they have caused.