Before some well-deserved holidays for the F1 drivers, we witnessed a fiery battle lighting up the Hungarian GP: championship leader Lewis Hamilton has challenged Max Verstappen for first position for almost the entirety of the race. The Dutchman put on a brillant defence and he felt only three laps away from the checkered flag, powerless against a driving-strategy masterpiece combo by the #44 and the Mercedes' strategiests.

https://www.motorlat.com/notas/tecnica/12381/hungarian-gp-analyzing-the-brilliant-mercedes-strategy

During post-race interviews, Hamilton has once again stated to be looking forward for a championship fight against Max Verstappen.
“We’ve seen a big step with Red Bull. They’ve really taken a leap forward with their [Honda] power unit this year and it’s pretty great to see, they’re going to go from strength to strength and Max is naturally just... he’s not a youngster necessarily in the sport anymore. While he’s young, he’s been here for a few years” recognised Hamilton, who had some good words to spend also on Leclerc: "Charles is only in his second season, so he’s grown and I can only see him getting stronger and we’re already seeing some great performances from him this season and that one is definitely one to watch out for".

Beside mental games (great rival Sebastian Vettel is never considered in Lewis' quotes), those words sound honest referred to single races: Hamilton has always liked to be challenged and a single-GP contender has often reinvigorated him. But if this battle would carry on all season long, it's not so certain that Lewis would come out on top.
Despite being undoubtely at least among the best drivers of the last 20 years, Hamilton has not had a true championship rival since 2016, when he left the Yas Marina track defeated. It might therefore be some rust to clean in his long-term fighting skills. On the other hand, youngmen Leclerc and Verstappen would be starving for a title and they wouldn't give up until the very last corner of the very last lap of the season.
While Leclerc, due to his lack of experience in Formula 1, has made some mistakes this year, Verstappen has proved himself to be flawless, with 21 races in a row finished in the top 5. Such a consistency, combined with his amazing speed, would for sure provide Lewis with a tough contender.

Something we have to keep in mind though, is that neither Leclerc or Verstappen has ever experienced the pressure of a Formula 1 championship battle. In Junior Formulas the Monegasque has proved not to crack but F1 would be a complitely different scenario.
Hamilton on the other hand showed no mercy (sportwise) already in this rookie year back in 2007, and this means pressure wouldn't be a big deal for the Brit.

https://www.motorlat.com/notas/especiales/12529/how-hamilton-039-s-security-operates-in-the-paddock

Drawing conclusions: would Hamilton outscore the two 21 years old in a championship battle? What we could speculate on is of course only the next few years, not knowning how the drivers will evolve in the long run.
Charles Leclerc at the moment might be a title contender but it would be extremely hard for him to come out on top. Experience is a key factor he doesn't own yet, so he would just need a couple of years more in the Circus to become a real threat.
Verstappen on the other hand looks to be ready. He has four and a half seasons in Formula 1 behind his back, and the steps foreward in his mentality he has lately displayed make the Dutchman really difficult to beat. Lewis would probably have a hard time trying to keep Max behind and he knows it.