SLAAC and Docker with dockered Pi-hole as DHCP server

Thank you. DHCP with docker-compose and bridge networking works perfectly for IPv4
However SLAAC for IPv6 also seems to require a host network.
Currently my router answers all IPv6 DNS queries instead of Pi-hole.
Does someone have solution for this?

Note that DHCP is strictly IPv4, and also that Docker is IPv4 only by default.

Pi-hole isn't involved in IPv6 address assignment via SLAAC.
With IPv6's SLAAC, a client would construct an IPv6 address (of possibly many) by combining an interface identifier it calculated for itself with an IPv6 prefix as learned by the router, as well as another one for the link-local fe80::.

You'd have to find a way to configure your router to advertise your Pi-hole host machine's IPv6 as DNS server and/or stop advertising its own.

You'd have to consult your router's documentation sources on further details for its IPv6 configuration options.

If your router doesn't support configuring IPv6 DNS, you could consider disabling IPv6 altogether.

If your router doesn't support that either, your clients will be able to bypass Pi-hole via IPv6.

Pi-hole supports SLAAC and it also works perfectly in host network mode.
I had this setup running for almost a year now.

My router doesn't support setting a different IPv6 DNS and disabling IPv6 is of course not an option.

Maybe - depending on your Docker configuration, Pi-hole's IPv6 services may be limited to Docker's internal network only. This would not have affected SLAAC IPv6 address assignment at all, since your router remains the source for IPv6 prefixes.

A different router that would allow you to control IPv6 DNS settings would be another option.

Yes but there is not an alternative router for the kind of internet connection I have (Hybrid DSL+LTE).
I am planning to put this router in a separate VLAN so I can set up an independent infrastructure