I had a backup copy of my whole 2018 installation. Installed 2019 'new' in newly named 'BIAB2019'and 'RealBand2019' besides the original folders on that external drive. Then copied (moved) without overwriting all the styles and RT stuff. Still waiting for the APh drive though.
Maybe the best way?

2019 seems to run OK, but some things are annoying; the style picker took a very long time to finish importing 3rd party styles. Searching in the songpicker you cannot use the keyboard letters to find songs starting with 'h' etc. Guess still some bugs?

But 64 bit !, havent tested the VSt yet, but 602 seems reasonably stable sofar ... F