I would like to write a custom elisp function that searches for a few variants of unicode text under a cursor and highlights their occurrences in the currently open file.
I took this as the task and wrote a function that highlights the variant of the symbol at point. It doesn't search for it, nor replace it. This way you can move freely while the matches ...
By default, lazy highlighting is lazy. It doesn't highlight beyond what's visible or has already been visible. You want to make it highlight matches everywhere, even those not yet visible.
Try setting option lazy-highlight-buffer to t. C-h v tells us:
lazy-highlight-buffer is a variable defined in isearch.el.
Its value is nil
You can customize this ...