Trade Republic
App's pretty meh and it's generally pretty meh but it's dirt cheap. 1€ per transaction is amazing when all I really do is passive investing.
They did notify me that they're going to delete my personal data when I hadn't followed up on my registrations for a few months which suggests they take data privacy serious and is the reason I ultimately went with them. Scalable Capital (another "cheap" neo-broker who I started the signup process with at about the same time) OTOH hasn't sent a word tome to this day; I should send a GDPR request soon.