Some landmarks for Djokovic at this Wimbledon

Already achieved:

1. 25 major finals (one of three all time)
2. Six or more finals at three of the four majors (one of two in open era)
3. 109 career finals (ties McEnroe for #5 in open era)

With victory on Sunday:

1. 16 major titles (one of three all time)
2. Five Wimbledon titles (ties Borg for #3 in open era)
3. Wins two or more majors in five different years (2011, 2015, 2016, 2018, and 2019), breaking tie with Sampras and Nadal and moving to #2 in open era
4. 75 career titles (breaks tie with Laver for #6 in open era)
5. 72 match wins at Wimbledon (breaks tie with Becker for #3 in open era - tied Becker with victory today)
6. 871 match victories (breaks tie with Agassi for #7 in open era - tied Agassi with victory today)

On cusp of guaranteeing with victory on Sunday:

1. Retaining #1 ranking after the US Open, thus confirming he passes Connors and Lendl and moves into #3 for weeks at #1 with 271+


Let's be honest. If he defends his Wimbledon title he's a near lock to get that weeks at #1 record. Like 96%. He's at about 85% as it is but still.
Let's be honest. If he defends his Wimbledon title he's a near lock to get that weeks at #1 record. Like 96%. He's at about 85% as it is but still.
I don't want to put percentages on it but I agree with your basic point. Losing the final, though, would certainly mean that record is not confirmed, not least because it would give Federer some chance of getting the #1 ranking back at some point.
I think this is what Djokovic needs to do to maintain his #1 ranking through the day after the US Open, which means tying Connors at 268 weeks at #1, and because there are no big tournaments for a few weeks after the US Open in effect means passing both him and Lendl:

Djokovic will have 12,415 points tomorrow. Nadal will have 7,945, and Federer 7,460. If we subtract all the points they're defending this summer, this leaves them with this guaranteed baseline the day after the US Open:

Djokovic: 9,325 [even with 0 points earned over summer, this de facto guarantees a ranking of #3 minimum after US Open]
Nadal: 6,225
Federer: 6,680

Given that Nadal and Federer are not due to play any warm-ups beyond the two MS events, their maximum point totals are 10,225 and 10,680, respectively - if one of them completed the summer treble. That's of course very unlikely, especially as Nadal may well not play Cincinnati and Federer may well not play Canada. But until that's confirmed, Djokovic needs 1,356 points to guarantee moving past Connors and Lendl for weeks at #1. He should get it done, especially as that's an absolutely worst-case scenario and if Nadal and Federer did play one warmup each, he'd only need 356 points, which is an MS semi or US Open quarter-final.

Federer has a good chance of getting the US Open #2 seed spot. The week before the US Open, he is guaranteed 6,860 points and Nadal is guaranteed 6,945. So he only has to outperform Nadal by 86 points in Canada/Cincinnati to nab #2.