Liam Neeson is on record saying he’ll keep playing action heroes until Hollywood decides to stop casting him in these interchangeable, progressively more derivative cash grabs (my words, not his). His character in “Blacklight” (2022), however, hopes to hang up his holster and play grandpa. But it’s not that easy if you’re an FBI fixer with obsessive-compulsive disorder. And when the death of an Alexandria Ocasio-Cortez surrogate threatens to unveil government wrongdoing, you know geezer hijinks, annoying camera gimmicks and eye-rolling journalistic hijinks will ensue. The film’s self-congratulatory wrap-up leaves too many loose ends and implausible decisions by key characters.