What is OOP today in practice if inheritance is dead, as you say, and mutability is out of style, as I've notice in all of the codebases I've worked on since ~2

What is OOP today in practice if inheritance is dead, as you say, and mutability is out of style, as I've notice in all of the codebases I've worked on since ~2014? It feels like we're just left with a heavyweight syntax for structs + functions bound to data, which feels like pretty thin gruel.