I don't see any reason why the land bridge AND the sea voyage theories are incompatible. No one can say for certain "This, and only this, is the way it happened." Clovis-type points have been found in New Mexico (No kidding! Near Clovis, in fact!) but also in the Chesapeake Bay area and in France. This does not prove that people from the Clovis area visited France, nor does it mean that in a great AH-HA! moment that type of point was developed in three different places at the same time. What it means is that we just don't know yet.

Was South America settled by people walking all the way from Siberia? Or did they use boats? There's a bunch of evidence accruing that people did both.

Rarely is anything absolute.