wow
first @langzi this is a great request, ferns are another “hard” taxa and we too have been struggling to make a breakthrough so thanks for asking
while agreeing that it is a bit difficult to have non grographic specific guides I think the 3rd link posted by @pisum is fantabulous.
I have been working on a “tree of life” kind of thingy (not sure what to call it so for now it is a thingy) - will share the output once it is in a shareable state :-) so the 3rd link is a great idea.
The other two links are also great, I like the smith et al paper as well.
Thanks