Armory starts now without the error, but then the same pattern repeats.

"organizing blockchain", CPU 50% and the log is filled with this line like a 1000 times maybe

 
For me, from the outside it looks like a endless loop somewhere.

https://pastebin.com/bkKTJtr9

P.s. This is an old but high spec professional grade machine with best components inside even if it is 5 years old.
If it can run CAD, adobe suite products, multiserver docker enviroments and really memory heavy IntelliJ Idea IDE at a decent speed it can not be considered ancient hardware in any means just because it has only 2 cores and usb2.