Update: repeat visit from another tech today because even with the fixed shock dampeners, it still made more noise than it should (albeit less now); after a lengthy investigation of a really-not-maintenance-friendly machine (welded front panel...) it turned out that one of the front concrete counterweights had shaken loose.
This was very annoying to figure out, because, well, the front panel was welded - they ended up asking in the repair tech group chat whether anyone had any ideas, and someone came up with the idea of concrete block tightening, and shared that on these machines you can remove the rubber seal and tilt back the machine, and then stick a hand inbetween panel and drum to get at the front blocks.
Took them a bit over an hour to diagnose, repair, and run a test cycle to confirm. Total cost was... 0 EUR, because it apparently fell under the warranty for their previous repair, being the same issue within the limit of 2 months. Awesome.
Hi can every electronics company be like this please, thank you