I watched a bunch of the record videos and contacted chess.com. It seems like most of the speedruns submitted that are WR times are actually taking advantage of weird loading bugs that are different based on browsers, devices, etc. I emailed chess.com asking about it and they thanked me for reporting it and they were working on patching the bugs associated with them and that they changed the behavior of bots from time to time so I guess new WRs will be possible in the future?