Vanadium hasn't been developed for other OSes in mind currently, it directly inherits the security enhancements from GrapheneOS like production MTE support and more rather than adding it's own inside Vanadium. MTE is currently exclusive to GrapheneOS since the stock Pixel OS only provides it as a development option with major caveats and Vanadium is the only browser incorporating it in production.

Even for platforms without MTE like other devices not Pixel 8 and later, having Vanadium elsewhere would be downgrade in comparison to Vanadium on GrapheneOS. Vanadium needs more before it could be positively received elsewhere.