Since updating to 20w09a on my server, nobody is able to use most console commands - they are simply not recognized by the game. The only ones that show up are /help, /list, /me, /msg, /teammsg, /tell, /tm, /trigger, and /w. I am a server operator; the server owner was not able to get commands to work through the server console, but could through PC-level /cmd/ prompts.