Hi @ben, thanks for the nudge.
I'm scratching my head with this one!
Because it's not really making sense, what I'd try myself is deleting all the installed haskell packages and trying to install the tidal library and its depenencies again from scratch.
You can try that with the following sequence of commands, but please take care, especially with the rm command which will delete the .ghc and .cabal folders in your home folder. It should be fine pasted as-is, but with a misplaced space, it could be dangerous. You might prefer to delete those folders using your file browser instead - but folders beginning with a . are generally treated as 'hidden' system folders, so that might not be straightforward.
rm -rf ~/.ghc ~/.cabal
. ~/.ghcup/env
cabal update
cabal install tidal --lib