For FB/Meta the decline is very obvious on the technological side as well. Nothing really works properly on their platform. And I'm not talking about their basic user features - I'm talking about the features that make them money.

Ad setup doesn't work, you are hitting random errors on setting up API calls, basic UX and non-functional pixel setups, some weird limits or even plain unresponsive pages.

Just few days ago, talking to their support about ficitonal ad account limit after hitting 5 ad accoutns, they responded to me randomly with system messages in vietnamese - my acc has never had association with vietnamese.