Although I suppose the headline doesn’t make much sense in that context - spacecraft systems are rarely in a “confusing state” (except maybe Boeing Starliner)

You only have to go as far as 'CQK' before there is, AFAICT and based on Wikipedia entries, essentially no even slightly important use of a TLA. There are then another >2k more or less unused, and if you go to four-letters, you've got ~390k to play with.