There is an ADAC report, that reports the number of road-side defects per car type that the ADAC was called to fix: https://www.adac.de/rund-ums-fahrzeug/unfall-schaden-panne/a...

And they do provide some statistics about running cost: https://www.adac.de/rund-ums-fahrzeug/auto-kaufen-verkaufen/...

However, both aren't that trustworthy, just better than nothing, because:

The first one about road-side breakdowns is frequently gamed by car manufacturers, because in leasing and warranty contracts they often require the use of their own road-side assistance orgs, thereby bypassing ADAC. So the more expensive German manufacturers are definitely underrepresented there.

And generally, ADAC has been known to produce unreliable tests and statistics: https://www.focus.de/auto/ratgeber/sicherheit/neue-vorwuerfe... https://www.sueddeutsche.de/auto/neue-enthuellungen-sind-auc...