Well yes but actually no. You can do everything that a bot can, how do you think the bot does it? You can make a bot token through the Discord api and slap that bad boy onto your requests and you can do everything a Discord bot can.
That’s how I made a verification system that doesn’t use an actual Discord bot running on NodeJS, so you can just get a code in game, tab to Discord, say the code there and boom, you’re verified on that account. All running on that Roblox server.
I just tested your code and my code and neither worked, so I think it’s back to when Roblox requests and blocked to the API on Discord’s end, so you would want to use a Proxy to bypass that.
You probably shouldn’t post your webhook publicly; now anyone can use it! It seems that someone’s gone ahead and deleted it for you, so that might be why you’re getting that error.
Actually, I just tested in Roblox studio, so it could be that the Studio header is blocked, but the actual servers aren’t. Is it working in studio and in game for you?