Yeah you're right. Thinking about it after I wrote that I thought there's no point changing to a Bosch if I'm so happy with the Yamaha. I am changing to a full sus but going to stick with the motor I know.
If you are changing to full sus anyway, it would be worth trying a Bosch.
They do ride slightly differently, the Bosch being a bit smoother and more refined.
The Yamaha motor is probably on a par with a Bosch, possibly the Performance version.
I've not tried a CX, but the Performance has noticeably more poke than the standard, so I expect the CX will be pokier again.
In other words, you can believe Bosch when they say the CX has more torque, even if the quoted figures are meaningless in use.
Another plus for a new Bosch is the option of a bigger 500wh battery.
On t'other hand, Yamaha bikes have a standard size front ring and can run two rings at the front.
Superior, in my view, to the tiny front ring on the Bosch bikes which I see as giving no advantage.