One time … landing page?

I’m building a Drupal 9 site and would like to have a one-time landing page that any visitor sees with various images when they first visit, then if they click on any image, or anywhere on the page for that matter, they go to the site’s home page, which stays as the home page for the remainder of that session. It’s sort of a like getting a splash when you first visit home, only I don’t want a modal, I’d like an empty page save for the images. I’m having a heck of a time figuring out how to do this. Does anyone smarter than me have any ideas? I don’t even know what to call this one-time landing page.

Splash Redirect claims to do this with a cookie:

The main difference between this module and ones like Splashify is that Splash Redirect sets a cookie to "remember" whether or not a user has seen your splash page.

This module is only available for Drupal 8 but you can either port it to Drupal 9 yourself or use the code as a reference.

P.S. If you're having trouble googling for this, it's probably because you want a splash page, not a landing page.

A landing page usually refers to:

a standalone web page, created specifically for a marketing or advertising campaign. It’s where a visitor “lands” after they click on a link in an email, or ads from Google, Bing, YouTube, Facebook, Instagram, Twitter, or similar places on the web.

You would want a landing page if you were creating several different landing pages for various ad campaigns and sending different groups of users to each one.

In your case, though, it sounds like you want all visitors who come to the site from anywhere to go a single page, and then get sent to the home page, which is probably more commonly called a splash page.