I'm trying to get the achievement for Speed Baking 3. It's tough. Is it even possible without cheating?
Yes it is. I never cheated and got most achievements. It is key to start clicking a lot! And focus on the upgrades that increase clicking power. Don't just blindly buy any upgrades but plan your upgrade path so you don't waste cookies on upgrades that won't increase your income significantly.
See also this information page for a strategy about getting the achievement.
It is possible, but I REALLY wouldn't recommend it. You'd have to be getting consecutive golden cookies with frenzies and click frenzies every time, and overall it's super RNG-based, took over 120 tries for me to get. (Sidenote-I also used an auto clicker). Ofc, you also have to invest well, but honestly I just bought whatever was cheapest and it worked out.