There is no such thing as a safe cracked version of any modern, popular software. The economics of cracking don't work in your favor. Hackers do not spend hours cracking software out of the goodness of their hearts. They do it to make money. If you aren't paying for the software, the software is paying them by using your computer as a mining rig or a spy device.
You can get FL Studio via Splice for $9.99/month. After 20 months, you own it forever. If you stop paying, you just lose access until you resume. This is the easiest way to go legit without a huge upfront cost. fl studio cracked safe