Standing in the dimensional portal block to the nether in the beneath won't work, it never teleports me to the nether. It should be noted that it does work if i'm in creative mode.

I can't think of any possibly way VSD could interfere with other mod's Interdimensional teleport because it doesn't modify any vanilla or modded code or object states related to that. The only exception is the nether portal disable feature, but that only prevents igniting an obsidian frame into a portal, not the portal's functionality itself.

Are you sure the dimensional portal block is supposed to work in the beneath. And are you sure that you didn't confuse this mod (Vertically Stacked Dimensions) with the Stacking Dimensional Rifts mod where the portal is actually from.

Pretty sure that @Lbphero confused the two mods