Problem with server

Im having this weird problem and for the life of me cant fix. I started at rlcraft server today and tried to join and it said registry missing so i fixed all the mods and it still didnt work, i figuerd its a config problem and just copy pasted server config into client config. I could join the server but everything was extremely laggy and weird. Im wondering if someone has an idea on what could be the problem in the config files ☹️