does loadstring still work? loadstring(print("hi"))?

Yes it works, only, loadstring is turned off from your game for exploit purposes

It works, you just need to enable it in ServerScriptService.

Also, loadstring returns a function, so loadstring(str)()

research plz

I recommend sandboxing the loadstring on the server using setfenv to prevent it from destroying your game.

If you want to run code in your own game (and only you) just press 'f9' in your game and go to "Log" and navigate to "Server." At the bottom of the Developer Console Window there will be a box for pasting code that is ran on the server.