just logged in after years of not playing and all my horses are gone - they were in Heidel - alsom my money is reset to 100.000 - which makes no sense.

am i missing something?

according to your account information its correct, maybe you log in wrong region.

While you were not plaing for those years the game devs made quite a lot of changes to the game. One of those changes was the removal of silver in the storage. All silver is now in the player inventory except what is in the central market. I am not sure where your horses went but if they were all tier five or lower they are easily replaced with better ones by capturing horses. The wild horses are now all tier six or higher ( never seen any but t6 myself).

How many years?  The game changed publishers from Kakao to Pearl Abyss in early 2021 and if you didn't apply to transfer your data by May 31, 2021, then it was not transferred and is lost.

They couldn't transfer without your express permission, so if you didn't sign up for it at the time, your data was deleted.

If you last played *after* the transfer, then make sure you are logging in to the right region.

I did transfer - just in case ;-) - but ty :-)

how do I find out which region my horses are in if that is the case?

If you are playing through web client you get a choice of playing on the NA server or the EU server. If you are currently on the NA server, which you can check by looking at the mini map, you could try swapping to the EU server when you next launch the game.

I am unsure how you would do that if playing through Steam.

I am also unsure how you have what silver you have if you are on the wrong server. 
Do you have any items in any storages? Do you have any items registered on the central Market? Do you have any alts?