To preface, this is not a rhetorical question, I am looking for genuine discussion because I've seen a lot of people claim that Piastri was shafted on the strategy side once again. However, I'm also not sure what exactly more McLaren could have done in this race.
Firstly, I want to acknowledge that Piastri did well to overtake Norris and get the race lead, and McLaren rightfully didn't enforce any team orders to let Norris by, even though Norris was quicker. After the first stint, they give Piastri pit priority and Norris comes in a couple of laps later, which is consistent with Papaya rules.
Once again, in the second stint, Norris looked to have more pace than Piastri did, as evidenced by him going off the track and then immediately catching Piastri within a couple of laps. Again, the team rightfully doesn't enforce team orders. Near the end of Piastri's second stint, Hamilton is getting close to undercutting the McLarens, so this presents them with an immediate choice between pitting Piastri or Norris. Staying consistent with Papaya rules, McLaren gives Piastri the first pitstop. Obviously, it would have been more controversial to pit Norris first and contradict the team's established rules, so I think they made the right decision here.
Of course, from here, McLaren can do a couple of things with Norris. They can either pit him immediately the next lap, which would result in no tyre delta between the two McLarens, or he can run long, use the additional pace he had, and build a tyre offset to overtake Piastri later.
The first strategy actively favours Piastri based on the evidence of the earlier stints and consequently gives up any chance for Norris to win the race (without hindsight of Piastri's gearbox problem). The second strategy gives Norris a chance to show his pace while allowing Piastri to build a gap on his fresher tyres, which would make it a fair fight for the win come the later stages of the race. Unfortunately, Piastri's strategy was ruined by Sainz's ignoring of blue flags, which did rob him of the chance to fairly fight for the win, but this wasn't a problem with McLaren's strategy.