“But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.” Galatians 1:8-9
Please show where the apostles taught the assumption of Mary or veneration of her.
Simply put, they don’t.
Or rather they do not in the way that later Catholics did. Mary has always held a special place, as the most blessed woman (she was the mom to Jesus). But the later traditions developed over time.
For instance, the Orthodox had a Tomb of St Mary. They believed she died, while many Catholic believed she did not.