curious In an imaginary world it could well happen that most conservative democrats and the non-trumpist and a bit more progressive republicans join into a new middle-field party. Nothing would stand in the way of this happening.
Very well might happen soon. If Ron DeSantis gets in with his Trump-like ideas (e.g. shipping illegal immigrants from his state to Martha's Vineyard in my state) I wouldn't be surprised at all if liberal-leaning Republicans and conservative Democrats banded against him to have more of a voice.