I'm not so sure that Max doesn't let Alonso or Checo pass him just to have something to do in the race.
From Reddit. They tell Max he can't get fastest lap and to just bring it home. Max gets fastest lap.
Lap 60:
Max: What's the fastest lap?
GP: It's a 16.6. It was a first lap on a new soft for Checo with DRS. So I wouldn't worry about it Max
Max: What's my fastest lap?
GP: Yours is a 17.3. Like I said, you've been given a black&white flag so we cannot afford anything
Lap 62:
GP: Mode 7, please Max. Mode 7. There's now five laps remaining. Okay, now can you bring it home within the white lines? Thank you
Max: Yeah yeah
Q: (Ben Hunt – The Sun) For Max, just bringing it back to you. You were obviously told to keep within the white lines, risking a penalty. You kind of ignored that and just pushed ahead and got your fastest lap and the bonus point. Do they tell you off - the team - after doing that? Or do they give you a little bit of freedom to get away with things like that?
Max: Well, I kept it within the white lines, I just went a bit faster on the lap. So I didn't do anything wrong. They don't know how much pace I have in the car, right, when they tell me this is the fastest lap, don't bother, but I knew that I could do it. So yeah, I just had to keep it within the white lines but this is something I think we can laugh about already. I was laughing about it with Helmut after the race so I'm pretty sure that they're quite happy.