Smoothing open / close command for a sliding gate

First, I'd like to say I was about to give up searching a site dedicated to electronics.
I'm discovering the amazing amount of knowledge stored in your site. Thank you to staff and members contributing to it. I'm 68, retired, former electrical engineer (but never pratice it)
This is my question : my sliding gate is driven by a 24 V DC motor (7 amps max). It's a CAME gear. Maybe 10 year old. New systems provide soft start/stop command. This one doesn't.
I'm thinking of converting the square voltage into not so square signal. Could somebody tell me if a RC circuit could do the job ?
Thank you for your help

PWM control (google for that) is probably the best option.