I had a similar issue several years ago when I had to replace the Brand X television that came standard with our travel trailer. I also purchased a Samsung Smart TV and, like you, quickly discovered that the original bracket fit the new Samsung, but all of the connection points for the wires were now hidden.
In my case, the TV was not on a swinging bracket, but it raised and lowered from inside a cabinet. Fortunately I had enough room between the back of the TV and the bracket to add four small blocks of wood (spacers) which gave me enough room to make all the wiring connections. I had to purchase a 90 degree fitting for the cable input due to the location of the cable connection on the TV, but that was it. Hope this helps.