An easy way to enter trim mode is to select the cut with the ALT modifier key pressed. That way You can limit your selection to a single track without having to activate or deactivate tracks.
The ALT key is also perfect for selecting large chunks of clips in segment mode.
And as others have said before: practice!
The most difficult thing isn’t really learning a new system, it’s the going back and forth that can be a bit confusing.
Cheers!
Erik