URL params don't work properly

I had a workflow with a navigate To option, in which I had a query param with an integer. I was able to retrieve correctly the integer from the Query object in my other page.

And then I learned that I can add URL params from the page settings, which display in the navigate To action which makes everything look nicer. Except that for some reason, if I try to use this URL param to retrieve the same integer, the editor shows me the state correctly but when testing, the value is… nothing. toNumber returns the correct value in the editor, but returns NaN at runtime so supabase actions fail.

I tried running the workflow in On Created, and On Mounted (it needs to fetch data for the page and set variables before setting the rest of the elements). is the URL param simply not usable when the page is being loaded ? (and even after, it seems).