How to "redirect" users from a given URL to a different page every time

Dear Community,
I’ve got a question

In practical terms: How do  I “redirect” any Ideation Link to send to another page instead?

In technical terms:  How do I "redirect" users that visit a  URL that contains a specific string (community.mycompany.com/ideas), to a different page we have defined (“new URL”)?

I know of a Third-Party-Script that was shared with me by the amazing Lauro from Support (shoutout)!

This one works fine ✅  But it only applies to URLs that exactly match “old URL”.

<script>
if (window.location.href == 'https://community.mycompany.com/ideas') {
  window.location = "new URL"
}
</script>

Now I don’t want only URLs that exactly match https://community.mycompany.com/ideas

The one below did not work well ❌

<script> 

if (!window.location.pathname.startsWith('/community.mycompany.com/ideas')) { 
window.location.href = "new URL"; } 

</script>

This is the one I actually want to use, so for all pages that contain the string community.mycompany.com/ideas, so any kind of ideation content, including the homepage.

It did not work well, meaning: any destination page kept reloading.

Does anybody know what I might be doing wrong?

Or is there an alternative, better solution?

Thank you so much in advance,

Daniele