Brexit does seem to have been a general loss for Britain.

But I'm very distracted by Germany - what happened/is happening there that they're faring so much worse than, say, France? (And in several of the cited measures, worse than the UK too?)

Germany is an interesting one.

One factor I think is the early EU days German growth was artificially high, juiced by cheap credit from German banks to peripheral countries which was then cycled into purchasing German industrial goods.

Previously peripheral countries had more indigenous industries protected by FX rate as well as some trade barriers.

The GFC broke this cycle, though it couldn't have gone on forever with or without the GFC.

Then Germany also kneecapped themselves in terms of energy policy, shutting down cheap nuclear power supplies and becoming dependent on Russian energy exports.

I've generally heard it as manufacturing woes due to competition with China. in particular germany used to sell a significant number of cars to china, and now is being outcompeted (both in china and many other locations) by chinese cards. plausibly true in other manufacturing areas, I don't know.

I'm not sure what's happening to Germany, but I suspect fax machines are involved.