<Html
zIndexRange={[16777271, 0]} // Z-order range (default=[16777271, 0])
the modal should either be op top of canvas or have a higher zindex. that means you need to lower the range on the drei/html element.
btw there was also a new release yesterday, html will now naturally occlude https://twitter.com/0xca0a/status/1609939896155652096