I am happy with this workplace, not perfect but near to it.
Arbeitsatmosphäre
Open Office Rooms shows an open community and are very good for quick communication between colleagues, but for tasks where you need high concentration you should probably get you own Noise-Cancelling Headphones.
Vorgesetztenverhalten
this mostly depends on the department and the team. There are Team-Leaders which are very new as a lead and don't have much experience, which you gotta feel. But there are also very good leads which know how to lead a team.
Umwelt-/Sozialbewusstsein
Caring about the environment: Yes, definitely. Digital First Company which has one of the newest office in Berlin (passive and modern tech inside)
Social: Yeah, maybe?
Trade Republic is doing very much for their employees, but it still didn't have works council (I also didn't feel very encouraged from the employee to found one).
And as other topics: It is a StartUp and a Bank. So I guess that TR is doing like you expecting such companies.
Gehalt/Sozialleistungen
In comparisation with other banks (important banks!) Trade Republic is paying a competitive salary with also some good benefits.
Karriere/Weiterbildung
At Trade Republic the people have the opportunity to proceed in their career. There is a budget for trainings/educations and often there are internal job offerings so that even Customer Service employees have the opportunity to work in better departments.