thank you for trying GeoQlik. From your description, it is hard to figure out what could be the problem leading to this perf issue. Except RAM or disk space issue, nothing is obvious here. GeoQlik for Qlik Sense is both rapid and stable.
The best would be that you send a recorded video and/or the app if you can to the team (firstname.lastname@example.org) so we can determine if it is a machine related or a config issue and provide you with a solution. That is the best way to move forward.