I am no programmer and am not sure if I am allowed to post this here, so delete if you want.
My suggestion: Like the default sort for posts we need a default sort for comments. There should be a dropdown menu like there already is for default sort posts.
Default comment sort needs to exist in the lemmy back end first. Open up an issue for this here first if you would: https://github.com/LemmyNet/lemmy/issues
There is a issue for that already