Hi Niko,
While ASM do not have a CRC checks, if you deploy ASM in front of this website you will significantly reduce the likelihood of a remote defacement attempt to succeed.
Your use case is pretty unique because most of the websites today are dynamic in the sense that they either will display a different page to a different user ("Welcome Niko"),or that the rate in which the pages content is updated is really fast. I'm not hinting that these challenges cannot be solved, but if you do have a WAF, and it is configured properly, the risk of defacement is really low.