The greater dragonmark feats aren't available. It doesn't seem to recognize the race correctly and allow it to be selected. Any one else having this issue?

It's not a bug, the greater dragonmark feat has been removed as it's not compatible with the new, official versions of the dragonmarked races. Instead, each dragonmark race has it's greater dragonmark feature already built in.

Also, dragonmark races no longer use inspiration dice (at least, they're no longer explicitly called inspiration dice) and so the feature from the greater dragonmark feat doesn't interact with anything in that regard anymore.

Which is sad, because I really liked greater dragonmarks and spells of the mark do nothing for non-casters (and little for half casters).

Just to correct something: the feats have NOT been removed.

They are not included in the new book and no longer apply to the new races but they are still available on D&D Beyond. Turn feat prerequisites off and they will show up. After adding the relevant one you can turn the prerequisites back on if desired. So if you still want to use the feats, perhaps because you've homebrewed back in the old (better) versions of the races, the feats are still available for you.