This is almost irrelevant, if a site really wants to fingerprint Vanadium on GOS, there are better ways to do it,
So many devices use Mali GPU and use Chrome. You will not gain anything by spoofing it. Also read:
https://discuss.grapheneos.org/d/19692-vanadium-fingerprinting/4
GrapheneOS Being on Vanadium does mean several things are different from Chrome due as not having WebAssembly by default due to the JIT being disabled by default, being on the latest stable / early stable before it's pushed out to most Chrome users, etc.