I've been using a Cintiq for years now and couldn't imagine going back to a mouse. Hand movement will depend a lot on palette placement your use of Wacom's customizable on-screen menus. I just upgraded from the old 21" model to their latest and greatest 32", and I'll admit that there's some adjustment, largely due to my aging eyes. For example, at its finest resolution I found the palettes and menus to be way too small. It's a ton a screen and to be honest I'd probably have been just as happy with the 27". Combined with a 27" iMac, this takes over the entirety of my oversized desk. When positioned as a monitor, I keep pushing it further away as it really is imposing.
But I'm slowly getting used to all of the optional menus and extra modifier keys that I didn't have before, and customizing those to reduce menu and keyboard use is making a difference. The newer models are really remarkably customizable.
I opted to get their flex arm this time instead of the ergo stand and it was a good choice. It makes it really easy to transition from a drawing tablet to a second display. An adjustable height desk makes a big difference as well, since you can lower it down to get the screen at just the right drawing height. And you might find too that having a desk without a middle drawer helps to get the screen kind of sitting in your lap.
Also, the current driver and firmware is a bit buggy, which I'm sure is part Mojave. But they just released a version yesterday that seems to have fixed the main issues I was having, so fingers crossed.