Yes this isn't possible in the current release of Tidal which is all cycle based.
However I have been working on this recently and this kind of 'stepwise' function should be in the next tidal release. There's a bit of info about it here: Step-oriented functionality by yaxu · Pull Request #1072 · tidalcycles/Tidal · GitHub
I'm still working on it, but as things stand you will be able to do what you want via
d1 $ s_nth 3 (# speed 2) $ s "bd sd cp ht"
Also there will be a function for polymeters called s_polymeter