Thanks for your very helpful guidance eoinbyrne!
I integrated the libraries now and was able to fulfill my usecase easily with that.
I have created a documented package that includes:
1 Action that encapsulates the moment.js library
1 Action that encapsulates the moment-timezones library
1 Action to directly get moment.js + activated TZ handling (to reduce overhead in usage)
If anyone else needs this moment.js package implementation i will update my initial question and attach it as complete package there!
Again, thanks alot.