There are two possible explanations for Kimi beating Giovinazzi. One is that Kimi has still "got it", his motivation is as high as ever etc.
I strongly favour the other explanation. After all, here's a guy who spent two of his prime years dicking around in rally cars at Ferrari's expense, when there were F1 drives available. Motivation as high as ever, I'm sure.
I'm afraid I'm of the Helmut Marko school. If the young one isn't fast enough, drop him and plug in another one. One of the best ways of finding talent - and it's not very sophisticated - is giving lots of drivers opportunities.