Can you use an iMac's internal Fusion Drive as your Time Machine drive?

I have a 2017 27" iMac, with 40 GB of Ram and a 1 TB external SSD. I'm currently running Sonoma 14.7, but I'll be upgrading to Sequoia soon. The internal 2 TB Fusion Drive currently has macOS 13 Ventura still on it, not being used (from before I got the external SSD and used OCLP to update to Sonoma).

So it is practical to convert the internal 2 TB Fusion Drive to be used as my Time Machine drive? Anyone else here doing something like this? Any tips or pitfalls to doing this?

Thanks in advance!