Scrolling / Searching in Library stutters/too slow

Hi all,

I think, that this could be a known issue, but I just want to clarify this.

I use the following set up:

MacBook Pro 15" 2017
Intel i7 2,9GHz
16GB DDR3
Radeon Pro 560
500GB SSD (internal)
1TB Samsung 850 Evo (external via USB-C)

Rekordbox Version 5.3.0
Database on internal SSD
Music on external SSD (80k)

Controller DDJ-RZ

Now the issue:
Startup of Rekordbox takes about 5 Minutes
Scrolling in Collection or single folders is much to slow
 - it starts not instantly when I scroll with touch pad oder "mouse wheel"
 - it stops about 2 to 3 seconds later after I stopped scrolling
 - using the search knob on DDJ-RZ is nearly unusable as it is even slower

Any hints what I can do to make it smoother?

ADDITIONAL INFORMATION: If I disable Waveform Preview in Library it is working as expected. But I do need the preview to identify the different versions.

Regards

Stefan