Specifically I'm wondering if as Columbus was casting about for funding of a Western passage to India that would've rebuffed him b/c those Sagas indicated that the passage might be blocked by another continent.
While there will always be more to be said on this topic, I summarized the basic current academic consensus on the Vinland tradition in pre-Columbian Europe (and after Columbian 'discovery' of America) before in:
+++
those Sagas indicated that the passage might be blocked by another continent.
None of (genuinely) medieval texts that allude to Vinland explicitly states that Vinland was another continent. On the contrary, the oldest and continental source, Adam of Bremen (c. 1075) actually refers to Vinland as an island located somewhere in the ocean.
On the other hand, As /u/sagathain, /u/epicyclorama, and I briefly mentioned before in Did the Vikings who reached America think they were in Africa and Why did the Scandinavians forget about the SKraeling (Inuit Peoples) after Viking Contact?, some medieval Scandinavians apparently assumed that Atlantic islands including Vinland had somehow connected to Africa. If we accept this hypothesis, they didn't require another continent to explain Norse encounter with 'other' groups of people like Skraelings in Vinland.