I like easy toolhead change idea for Ender but found one quite popular design seems not tough enough and feel like it above the plate. Then found Quick Fit by lukie80 but its for Prusa. I like the Quick fit design that work in the plate than previous one altough it seems too big also. Already see several remix for Vslot gantry and slim version of it but I still decide to design (maybe as transition before I mod X gantry to Linear shaft / rod) version to my Ender 3 max gantry.
Im sure not using D-Sub Electrical contacting and center hole in base plate but still using it on the plate just to be compatible with original design and to save material. You can use wiring design used in Quick tool if you want but right now Im already satisfied when I just can easily release the toolhead to clean it or change nozzle :)

Already try to print and install seems very fit to gantry as I use gantry STL file to help designing. It is snap properly even before install all nut because there is small corner pit to hold it with heatsink hole in front. I include plate design for Ender3 max stock fan holder but bcause Im already not using stock fan holder Im not tested yet. I already test to install my old fan holder, it fit there but not use it on real use, so can inform on comment if you either have problem or use it ok :)

After I try, unfortunately you need to loose/extend cable because it sit higher than before on left lever.. nozzle position shift around 8mm on Y (seems loose built size by that) You can adjust Y endstop switch or just print over 8mm on Y (I choose this)
Compatible with Klackender, I include backside photo.. already use without problem even with slightly moved location
Update 19/6/2024:
I include QplateE3MaxSt.stl slightly thinner plate (on wing only) for Ender 3 max stock
Other plate that I plan to use maybe later come on other separate design :)