Are there not ports in Texas and Florida that can handle these ships?
Yes but the ships from the Pacific have to go through the Panama Canal (and pay China $200,000+ per ship) to get to the Gulf or Atlantic ports. Amazon, Walmart, and others already made arangements to do this when they realized what the California emissions changes were going to do to the West Coast ports.
The container port of Ensenada Mexico, 110km below the border of US, runs trains to the US. They are not as big but it is a work around. Problem is the ships waiting cannot switch to a foreign port from where their cargo was bound.
Sure, but Panama Canal passage would jack the shipping cost.
In addition to the already mentioned panama complications, you are also adding UN planned for loads to those ports over and above what they may already be dealing with.