Hello,
the lte interface getting ipv6 and i can ping google ipv6 dns ip: 2001:4860:4860::8888 on the router but not on lan clients.
The isp isn't providing prefix delegation. So dhcp v6 client is not working. Only way to get the ipv6 from the wan to the lan clients over the bridge is RFC7278 or nat64.
For my mobile isp (O2 Germany and many other mobile isps) it's for ipv6 on lan side necessary the router is supporting RFC7278 to get ipv6 to the lan side.
They are seemingly using this method for ipv6 deployment:
https://datatracker.ietf.org/doc/html/rfc7278#page-3
The Mikrotik Chateau routers are not supporting RFC7278. This should be the reason why you cant use ipv6 from the lte interface on lan side.
There is no reason why Mikrotik is not implementing RFC7278 on a mobile router. Mikrotik your clients with cellular wan interface can't use IPv6 for their devices.
Best regards
JSD42