I do remote uncoupling with my Zimo decoders using the a standard Kadee couplers and servos. Most difficult part of this process is finding where to place the servo.
My LGB Davenport engine was done with front and rear uncoupling via the Zimo decoder and my parts cost (servos, kadee coiupler, necklace chain) was under $20.
I drilled a small hole in the kadee knuckle and screwed the end of the chain to the coupler.
I glued the servo with quikgrip to the bottom of the engine. (I use this glue as it sticks well to LGB plastic and can be peeled off years later {Servos can go belly up and need replacement) like a post it).
Next I programmed the kadee to operate.
Now I can tie the chain to the servo and fine tune the opening and closing of the Kadee.
The zimo decoder can be programmed with the ‘waltz’ feature, that is at the press of one button in DCC. Tthe engine backs up, opens the coupler, and then pulls forward away from the car all by itself. Now with the coupler open you can push/hump the car without coupling. Pull forward and turn off uncoupling.