Hi islek.lukas24,
We will suggest you making animations done in iClone and have your VFX done in Unreal.
Thanks for raising this question up and I am sure many user has the same question as you.
I'd also like to recommend some iClone Python Scripts for you, as some are very helpful in animation editing in iClone.
https://marketplace.reallusion.com/iclone/plug-in*Just note that some plugins may not also be compatible with Unreal. If there's any specific plugin that you want to ask, you can reply or pm me for answers, thanks!