Thanks. It works on Windows too. It remains that the opacity update is sluggish compared to the CTRL+T workaround that makes it very very smooth (a real real-time) and I wonder why. I will keep using it whenever possible.
Been having this problem for a while now on macOS 12.3 and 12.4, it's very annoying. I believe it's related to the navigator somehow since opacity changes appear in real time in the navigator but not in the main window. I tried updating/downgrading Photoshop and it doesn't help