Chess coding

I have created a game of double chess called Synergy Chess. This is live as a free online game that people can play against human or bot (not an app - web based only). I am not a coder. I hired someone to write the program. The game is written in ReactJS, NodeJS, Xitrium, Scala and Java. This makes it very hard to find quality people that can actually work on the coding. After doing some research on Wikipedia I have noticed that chess dot com was created 15 years ago and is written in Java, JavaScript and PHP. They currently have over 100,000,000 registered online players.

I am trying to find out if chess dot com is still written in these languages. if it is, then it should be feasible that Synergy Chess can be simplified to make it easier to work on. I may need to start again and have the game written from scratch. I am looking for solid advice from real coders regarding this issue.