We (SaaS, https://geocoder.opencagedata.com/) use https://quaderno.io/ plus their Stripe connector which handles inter-european VAT well. It takes care of invoice PDF generation, UI for users to change their billing details, list of past invoices etc.
Yes, as mentioned in my other post, ChargeBee does this really well. We, as a German company, use it for our SaaS offering.
Do they also do revenue recognition for you?
Revenue recognition isn’t something I know anything about (see my comment above about chargebee doing a bunch of stuff I don’t even know I need) but here’s their page on it
Especially for Germany/Europe?
If not, why not? Sounds like a good business opportunity.