In order to change the volume of a selected audio event, you have to double-click into the (red-circled) volume box on the top right.
In order to change the volume of a channel, you have to single-click into the (red-circled) volume box on the left.
This inconsistency means I can’t build muscle memory to navigate volume UI elements, and I routinely do it wrong, which usually means I double-click in the volume box on the left, which will then usually put the cursor between two numbers, and when I type in my desired volume, it’ll end up being a nonsensical number (since it will be interleaved into whatever numbers were in the field before).
I just tested on my end. If I’m understanding correctly, I clicked on those to areas in order to change their values. On my end, I only needed to single click both fields.
This still isn’t fully consistent in the UI. Even with this option selected, I need to double-click on, for example, the pre-gain field in the channel edit window if I want to change the pre-gain.
It’s really hard to develop muscle memory for quick workflow if some fields require a single click and some a double click.
I run into the same stuff on Cubase 12 all the time. I try to not let it hinder me but sometimes it does. Then I have to slow down, using cognitive thinking in order to be able to enter a value correctly.