View containing a recursive function

Hi all,

I have a recursive part in my database logic that I want to isolate and
reuse as a view. I had found a blog that explained how move a function
parameter into a view. The SQL is in attachment.
When I write a query based on that view with a fixed value (or values) for
the (input) parameter, the planner does fine and only evaluates the
function once.
However, when the value of the parameter should be deduced from something
else, the planner doesn't understand that and will evaluate the function
for each possible value.

Any pointers to what I'm doing wrong or on how to optimize it?

Attachment contains the queries and explain plans.

Thanks!

Kind regards,
Mathieu