I have a model of a sailboat and the sails do not have good topology - they are not composed of all quads and have some ugly triangles, etc.

Would this be a good use of the Remesh node to fix such issues rather than feeding the bad topology in to the solver? My understanding is the solver will use the existing topology to create constraints, so using a Remesh will create even triangles for a more uniform and accurate mesh for a cloth simulation.

Would this be correct?

Otherwise I would need to fix the topology and I don't think this is simple to get uniform quads since the mesh is distorted.

yes, you can remesh the sail for the sim

then for the render either use the remeshed one if it's suitable, or pointdeform the render version of the sail in case it contains details that were not necessary for simulation