Question about pre-purchasing tickets for Hida Takayama after line closure

I was planning to travel from Echizen to Takayama in the late afternoon/evening and was seeing advice to pre-book seats on the Hida limited express.

However, on the site to book even though I can see the routes, they are not selectable for booking, even if I select Sugihara -> Takayama which should still be operating.

Is this an issue with how I am attempting to book, or is the line north of Takayama currently unbookable due to the closure?

If it is unable to be booked, should I consider the alternative route of going south to take the Hida Takayama line from Maibara instead which is much longer but is all reservable?

by Kuinran