As far as I understood for the configs “format” (depending on the data type) you can reference for possibilities at MomentJS and NumeralJS. So whenever an element offers you “format” than you can look up there the options, but not just at any place in the App config I would assume. (see Screenshot for a reference in the docu)
OK, this seems like the way to go. Unfortunately, column elements in tables do not have a dedicated format attribute (which tbh puzzles me a bit since I would expect this option exactly there as many other visual settings can be done there). I suppose, I somehow need to define an element in the columnStyles section in global and then reference it somehow.
One thing remains: Can we also use functionality like the Time to now feature (see Moment.js | Docs) formatting the timestamp as time passed up to now (e.g. “a day ago”)? This would be the the optimal solution in my case.