You can, its just that TrueNAS has a lot of nuances to it, like you needing an Intel NIC. You can learn TrueNAS but I wouldnt put critical stuff to it as a beginner.
I did put critical things in it and lost data only because I didn’t know what I really needed to do. Somehow I know I am not doing things 100% right but it is probably good enough.
TrueNAS works beautifully as a NAS but I am not there because I want a beautiful NAS, I wanted a server appliance that I can put apps on it.