Freedom of speech is in retreat (2016)
economist.com
economist.com
If an organization like FIRE wants to defend the one particular right of free speech to the exclusion of all others, that's more complementary than antagonistic to the ACLU's mission. Or at least it should be.
Relating to free speech, I believe the ACLU from last century would generally oppose the ACLU of today.
For the 1st amendment, you might find this 2022 article interesting: https://www.aclu.org/news/civil-liberties/defending-speech-w.... It refers to ACLU history and lists recent 1st amendment support they've given to Trump supporters, the NRA, people making homophobic statements and so on.