A measure of your own
If the ranking can't tell you how your life is going, something else has to. It's no use being told to stop using a measure unless you're offered a better one, because the need behind it is real. You do want to know whether things are all right. I think two measures work, and you already have both.
The first is your own past. You're the only person whose full version you've had access to at two different dates. So comparing yourself now with yourself five years ago is the one comparison where both sides are complete and the start line is shared. It answers real questions. You can ask whether you're better at your work, whether you're kinder at home, whether you're less frightened of things that used to frighten you, and whether the money is in better or worse order. Some of the answers will please you and some won't. All of them are about your life, and all of them point at something you can do.
The second is your own wants, and here most people find a gap. Try this with the list from chapter 5. For each area where the dip tends to strike, write down what you want in your own terms, and what would count as enough. Don't write what would impress people. Write what you'd choose if nobody were ever going to see it. For home, you might find that you want a second bedroom and some outside space, and that you don't care about islands. For work, it might be more say over your week and no more travel. For fitness, to get up the stairs at the station without puffing.
If you've never done this, you've been borrowing. Without a written want of your own, whatever you saw last becomes the target by default. You drove to the housewarming with no opinion about kitchen islands and drove home needing one. A useful test for a borrowed want is to ask whether you wanted the thing before you saw it.
Once you have the list, the dip has something to be checked against. When it arrives, you can ask whether the thing is on your list. Often it isn't. You don't want to run marathons and never did, and the dip was only registering that someone had won at something. Those can be let go with no effort. Sometimes it is on the list. Then the dip has reminded you of a thing you want, and the answer is a next step, written down. You treat it as something still to be done. You don't treat it as a score.
There's some evidence that people who are doing well work roughly like this. In two studies from 1997, Sonja Lyubomirsky and Lee Ross had students perform a task alongside a peer who did better or worse than they did. Students who'd rated themselves as unhappy were strongly affected either way. Happy students reacted when the peer did worse and were largely unmoved when the peer did better. The studies can't say why. My reading is that the happy students were checking their performance against something of their own, so a faster neighbour didn't change the result.
You may wonder whether it would be simpler to look downwards. There are always people worse off, and "count your blessings" is old advice. I don't recommend it as a method. A study from 1990 by Bram Buunk and colleagues, with cancer patients and with married people, found that comparing in either direction could leave someone feeling better or worse. Looking at someone worse off can comfort you, and it can also show you where you might be heading. It also keeps you in the ranking business. You'd still be reading your worth off other people, only from a more flattering angle, and that angle will turn as soon as someone impressive walks in.
Appreciating what you have is a different act, and a good one. It doesn't need anyone else to be doing badly.