I have done this upgrade: in short I wanted a bigger nozzle, for improved flow (since the plus is quite big, and using a 0.4mm nozzle will simply take days to print anything bigger than I already could), and have a unified interface across all my machines.
I opted for the Duet Maestro for a few reasons: 1) it have ethernet (I used an ethernet extension, to bring it to the outside; wifi is going to struggle to get in through the chassis); 2) it have sufficient ports and connectors for everything on the Ender 5 Plus; 3) it is not as expensive as a Duet Wifi; 4) improved BL Touch capabilities compares to the Wifi (installing and setting up the BL Touch was simple easy and straight forward - on posts in this forum, I noticed it is harder to do on a Wifi or Ethernet).
I designed a mounting plate, that fits the Ethernet port, and is used as a mounting point for the PanelDue case.
I mounted an E3Dv6 Volcano; using the Petsfang/Bullseye as a mount (extended with a different blower fan mount). This part caused me to lose about 5cm in X direction, and actually gains a few cm in Y, but it works nicely.
I also upgraded the extruder to a BMG, and it is working great.
When upgrading, it is important to have all mounts and parts printed before you start (unless you have an extra printer, but to save time).
The heatbed is the thing that draws the most current, the stock E5+ use a big mosfet board to handle this - I decided to keep using it (technically the Duets can handle the current, but it is near the limits). Note that the Z axis have a shallow angle in the threads (it keeps the bed where it is left), but increases the z steps per mm.
I have been running this configuration since early in the year, and working great.