Hi, i found duckdns, but it seems like a docker for something like dyndns seems overpowered, is there a plugin for 6.4 out?

Nope.  And probably won't be.  

 

Running in a docker container isn't particularly overpowered as the container is probably sharing a ton of layers with other containers (especially if you're using the lsio version) so there's not much space in the image actually being taken up, and the container itself is just a script that updates duckDNS's server's with your IP address on a schedule.