Unusable for me as it won't let me force a specific route. Yes, a car can't drive through that gate, but I can walk through it with my bike. Auto routing is neat and all, but in the real world, cyclists need more flexibility.

Not as good as the project from the OP: I tried to connect two cities in Italy, Padova and Riva del Garda (because I know the cycle roads you could use to travel from one to the other) and this project perfectly nailed it, while cycling Brouter suggests low traffic roads but seems to not be aware of many cycle roads.

And it's forked frontend https://bikerouter.de

That link seems to be for an older version from 2021, the latest version is here: https://brouter.de/brouter-web