For entrepreneurship, I recommend the following Meetup group:

https://www.meetup.com/de-DE/StartupDorf/

For FinTech, the following two groups:

https://www.meetup.com/de-DE/Dusseldorf-FinTech-Meetup/

https://www.internations.org/activity-group/16962/wall?ref=gro_yg_ti